Thread: 2007 GP GXP Money Pit - Steering Pull, DIC Errors, Etc - Very Long...

Hello,

I used to have a 2007 Grand Prix V6, got totaled (act of god, topic for another day), bought the 2007 GP GXP about 4 years ago, 27 or 37k miles when I got it. Previous owner installed the Magnaflow CatBack exhaust and CAI branded cold air intake. When I got the car, it was throwing a misfire error - the plugs were fouled from AFM/DOD, which was corrected with new plugs. It started burning oil about 2 years ago (AFM / DOD related oil burning issue) - I had a shop do treatment on the rings (about the same process as in the service bulletin), and keep a couple quarts in the car and check it from time to time. It loses about a quart at about every 2000 miles. I get a lifter tap if the car sits for a while on a cold day, it pumps back up within a few minutes of starting it up. I go through about 2 front tires every year, rears every other year. I'm at 145k miles now.

A couple years ago, I backed into a curb and crunched the downpipe, so it got the 3" Magnaflow downpipe (cheaper than OEM), the one that has a cheaper / more free flowing catalytic converter. Since the downpipe swap, I get a P0420 O2 sensor error if it idles at a light for a while, so I have an Actron reader (cut the locking tab to fit the OBDII connector more easily - it gets used a lot) in the center console I use to check and reset the check engine light. I'd love to get rid of that error since it kills remote start if we forget to reset it, but that's a minor issue.

It got a TEP Street / Strip trans rebuild (sent mine in) at around 120k miles (last year) - the trans had started slipping / grinding. The TEP rebuilt transmission is THE best thing I've done for this car - much faster shifting, more firm shifting. It took about 2 or 3 months for the 1/2 shift to soften up, it was pretty aggressive at first. The rebuild has been very reliable, no problems or trouble with the rebuild. When the transmission was replaced, it got a new radiator for the TEP warranty, which brought the temps up, I've seen 220+, and it starts to slip at that high a temp. I ended up getting a trans cooler from TEP (inline with the radiator cooler) this year to remedy that, which has been another great addition - dropped my trans temp way back down, usually runs about 176 something. The trans cooler got installed when a trans line went bad - I did the one stock trans line and new cooler in the driveway, found that the trans line was run under the radiator hose which added a lot of tension and likely is what caused the line to fail, it was likely routed this way when the rebuilt transmission was installed.

When the transmission was replaced, it got a new steering rack, I forget why - leaking, maybe. All was well and good, until this year.

Right now, it has rack #3 in it (counting the one in it when I got the car), #4 will go in next week, and it has power steering pump #3 installed (first one was having a problem, second one had a problem, 3rd put in within the past couple weeks). It seems the rebuilt racks available just aren't very good - the last one, I think had debris in it - had a hard spot in one area, caused the pump to whine, the power steering would completely kick out at random.

I took it in earlier this year because of excessive tire wear on the outside edge of the front left tire down to soft rubber (no odd wear on any other tires), and it was pulling to the left. Front struts, strut mounts, front and rear tires (they switched from the Potenzas to a different brand - I forget which, but they're harder and slip a lot faster, though they were supposed to be about the same, the Potenzas I was told weren't available for a few more months), and rack were replaced, tie rod ends seemed OK, the shop told me everything else seemed Ok. The pull continued, so I took it back - I've lost count of how many times it's gone back - 4, maybe 5, or more?

About two weeks ago, the mechanic told me that they slotted some adjustment, something about 2 plates, one with a hole, the other with a slot, and that someone from GM told them that they slot the other one as a fix for W body cop cars (camber adjustment) - the steering seemed a little funny after that, can't quite explain, it feels like its mildly hunting for straight, though an alignment was done again. If I hit a really hard bump, it kind of wobbles really quickly (for less than a second, maybe a half second), then settles down. It does this weird thing if I cock the wheel left and gun it hard in reverse - the wheel starts to kick more left, seems to come from the front left, turning the wheel left. I've mentioned this to my local shop, but they didn't think much of it.

Last week, I purchased new front wheel bearings, new outer tie rod ends, rear struts and mounts (rear struts were shot) - and they installed all but the rear struts and mounts. I get the call to pick up the car, with "good and bad news". I'm told the car was aligned, but there was a problem with TPMS, 10 pounds off, AND 3 warnings coming up on the dash, and a new rack was going to be ordered, AND the belt tensioner needs to be replaced, but the car is OK to drive, and shouldn't be pulling left. The car will go back next week for what hopefully will be the final trip in - I seriously doubt this is the end of all of this. They'll then install the rear struts, a new rack, and the belt tensioner (I ordered that this past Monday).

Well, now it isn't ALWAYS pulling left, but it does pull left. Sometimes it leans right, but mostly still pulling left. The front left tire, replaced earlier this year, is showing the exact same wear pattern that caused me to take it in earlier this year, but I don't know how much of this is a result of wear while other things were tried - I guess I need to mark / measure the outer edge of the front left tire or something.

For whatever reason, the shop almost always puts 40 PSI in the tires. I've told them several times, the thing needs 30 PSI, like it says on the frame of the passenger door. At 40, the transmission doesn't feel right, acceleration is off, and the handling is way off. So, when they told me the TPMS was off (I check my pressure fairly regularly, work where there's a lot of metal for tires to pick up), I had my doubts. I told them the TPMS may take several minutes to update. They told me that they put in 40 to do the alignment (something doesn't seem right to me when you set a tire at 40 to align and 30 to run, but then I'm not a mechanic). When I got it home, I checked the pressure all around - twice. Approx 40, 40 left side, 30, 30 right side - and TPMS agreed with a cheap gauge, within 2 PSI - so TPMS is fine, but I'm 10 pounds high on the left side. I'm so frustrated with the thing, I didn't even bother to change the pressure - maybe I can wear the middles and insides instead of the outside front left!! I almost don't want to drop the left ones down, as I am fairly certain it's going to pull harder left when I do.

As for the alarms, I'm seeing 3 messages, stability, traction, steering - so I looked it up online, and found the speed sensor harness is a relatively common problem - opens and shorts can occur in the wiring. Magnasteer is disabled, the wheel is far more stiff than it should be. I called the shop and told them what I found (hey, I just want this thing FIXED, Guys!!), but they said they checked the coils and those were fine, and they could check further when I take it back, but they still were planning on replacing the rack - again.

Just today, I noticed something else - I checked G's, and lateral G's was 0.00 - this was after driving a bit. Usually, I can lean my body left and right in the seat when parked and get 0.02 easily. So this is a new problem!! Not sure where the sensor is for lateral G's, if it has anything to do with the work they did the other day, etc - but it's definitely something that has changed since the last trip to the shop.

The shop has been doing the right thing regarding cost - they aren't charging me for alignments - just the first one earlier this year. They aren't charging me for the racks, either - just for the difference in cost to a "dealer" rack (latest TWO racks, current and next). The belt tensioner was a surprise, though I know the pulley lip is chipped off, I think another shop did that - the local guys said it was leaking or something.

I'm at about 80k miles on the current plugs and wires, and I'm getting a random shimmy in the engine at idle, though no misfire has been reported yet - I haven't even bothered mentioning that to the shop, I'll just do the plugs and wires myself at some point, I guess.

When I got this car, I was in love. Lately, I get it back from the shop, lean on the throttle, and it just isn't fun anymore - the amount of money that's gone into this car in the past 4 years has just been sickening - I can't seem to get it out of any shop (I've had it at 3 different shops since I've owned it - a local trans shop that had no clue about this car, a tire shop, and my usual mechanics) for less than $1k. I've spent more than I owe on it. And lately, I can't look away from the road for more than a couple seconds before it starts to find a path OFF the road - like it's trying to commit suicide.

I'm... Frustrated. At what point do I just throw in the towel, and buy... something else, something newer, something that isn't going to rack up $1k every time I take it in?? That's what I'm asking myself. Parts are difficult if not impossible to find - the Bilsteins are no longer made, so the ones in it (and the two boxed in the trunk) may be the last ones it sees, and, well, just about anything GXP-specific isn't going to be cheap (ex, $130 something for a belt tensioner).

For now, the plan is:

* Take it back next week.
* They'll install the rear struts, strut mounts, belt tensioner, new rack (maybe, unless they find the speed sensor wiring to be a problem, then they may not).
* One more alignment?

If they come back with some other thing (at this point, I can't imagine what else that might be) that will cost me some ridiculous amount, I'll just haul it to a dealer and trade it in. Another $200 part would about finish me off, I think. It's hard to find something that I'd like as much as I used to like the GXP, though - something I'd be happy with. I've been thinking maybe a newer Buick Regal GS, 2014, 2015?

When I get it back (barring no crazy parts replacements), if it's still wonky, pulling left, I'll take it to a GM dealer - I've lost faith in my local shop, and I'm desperate to get it right. My thought here is, just about all of the parts that can cause steering issues have been replaced (only thing I can think of is that the control arms / bushings are bad - wouldn't that be a laugh?? $40 something each!!), so there's no reason it shouldn't be able to be tamed back to where it should be.

Beyond that, I've got hundreds of dollars worth of tires I don't like - but at least they'll last into next year. Plugs and wires need replacing. Then what? Bottom half engine rebuild when the rings finally gum up from DOD / AFM? I drive it over 300 miles a week, so disabling DOD isn't something I've seriously considered - I get about 21 MPG as it is!!

Any thoughts on the steering issue? At times I think maybe I'm just being picky, but the wear says otherwise. I've dealt with my local guys for nearly 10 years now, and they've been fair in the past. Last year, the alignment they did was perfect, but this year, well... And is there any way to tune out / fake out the P0420 sensor error?

I may have missed something, if so, just ask.

Thanks

I have heard for years that these cars eat money. I still wanted one but couldn't pull the trigger. You have found this out the hard way. Tires and transmissions seem to be the universal problem. I can't speak for the codes or alignment issues. I would have turned off the AFM as I was leaving the dealer; the mpg isn't worth the sticking rings/oil consumption problems. Surprised to hear your Bilstein struts didn't hold up. My GT eats front wheel bearings about every 6 to 9 months. Your GXP may have demons.
I sat in a Regal when my car was at the dealer a few months ago - hit my head getting in and out. A Lacrosse with the 3.6 (300 hp) would be a better fit for you and they are plentiful should you decide to bail. The 2013+ Buicks are certified for 6 years, 100,000 miles - give you something of a breather.

Originally Posted by ScottyDoggs

how about you sum up what wrong in like a paragraph? im not reading that wall.

Dude he's not being brief which is a relief on this forum. He's elaborating every detail to narrow down the problem. Give him a break lol.

I'm at work so I'll look it over again and try to help you out.

BTW, good grammar. Some people who ask for help on here can't properly construct sentences for ****.

Sent from my LG G3

get whatever you need replaced fresh to start and find a shop that does race car alignment, you want someone that does speciality alignments and is going to look beyond if its in the green on the rack monitor. Where I live there is a few places that specialize in it, but you pay for it, usually twice the price of what a normal tire place will charge.

LeadfootCJ7 - Thanks, I'll mention it to them when I stop by this week.

91parkave - Sounds easy enough. Magnasteer - well, THAT makes sense (errors on DIC). I wonder if the latest rack is the non-Magnasteer one.

mars5l - It'll be a challenge to find a place, I'm about an hour and a half from the nearest city. Nice winding roads with little traffic, but at a price. I'll have to do some research and see if I can find a good place to take it.

***

I stopped by the shop yesterday, but they were already closed. I'll try again today. I really hope this is the last trip in, but if it still pulls left, I'll take it somewhere else - these guys have tried and tried, and I really don't see a point taking it back again if it pulls left when I get it back. I've given up on them fixing the pull, I just want the rest sorted out, then I'll take it to another shop for the pull.

they gave you a printout from your last alignment? Is it always pulling or on certain roads it pulls?

Some alignments shops set the car up for road crown. Might wanna look into that.

Sent from my LG G3

mars5l - Yes, they did (they always do), but I may have thrown out the last one (I've lost faith in that paper!) - I can try to find it (or another recent one?) if you're interested. On the 2nd or 3rd alignment this year, they pulled the alignment from last year to show me where it was then and what it is now (to show me that the machine said it was more or less the same) - and last year, the alignment was the best it had ever been.

HighOctaneRacing - Yeah, I talked to them about how it's pulling, what conditions, which roads, which turns (I drive the interstate by their shop), many times - and at first, they suggested that the road I was on was what was causing the pull, leaning left on the left side, right on the right side - but on a road leaning right, it still pulls left!! It pulls way left on the left lane of a two lane road. If the road is canted severely enough to the right, it WILL go straight!!

At one point, they told me they found some bad ceramic bearings in their alignment rig, and even after replacing those and doing another alignment, same results. Meanwhile, the tire tread wear is pretty bad on the outside front left right now, the profile of the edge of the tread is getting worn down (4 new tires this year when I took it in for this specific issue, so two different tires on the front left, even different brands, wearing on the same edge). At this rate, the tire will be toast in another 3 or 4 months!!

At lower speeds (most of my driving is 62 mph+), around 35 or so, on a straight road that is leaning slightly right for a stretch with no bumps, I can push the wheel right to where the car just nudges right, let go, and it will go straight until I hit a slight bump (any tire, either side), then it pulls left, and will end up on the other side of the road in 6 or so car lengths - and once it gets to the middle of the road, the left pull fully takes over.

Is it better than it was when we first took it in this year? Yes, there was an improvement (it was pulling more) - right after the first alignment this year, the drive home and the first drive to work, it was quite a bit better - but still pulling left. It seemed to get worse (up to a point, then it stayed at that level) the more it was driven, and it hasn't been that good since. I've wondered if I'm shifting something around by how I drive.

Whenever the car goes into the shop for more than a half a day, I get a rental car. I've driven a few different rental cars this year on the exact same roads I drive the GXP on. ALL of these cars have alignments that are just fine. Ok, well, one was slightly dodgy, like the toe was a little off, but not nearly as bad as the GXP. It's irritating to drive a cheap-and-abused rental that tracks straight, then get the GXP back from the shop, "It's fixed!!", still pulling left. I almost look forward to getting a rental - that's just sad!!

I talked to the guys at the shop yesterday, and Tuesday is the next (last, if all that's wrong is the steering pull!!) trip to my usual shop for the steering pull - I'm willing to do a road trip to a shop that can set it straight. Anyone have any suggestions for a shop in Richmond, VA? Anyone at a shop in Richmond, VA want to take this on, solve it, finish it? Anyone have a GXP with a solid front end I can transplant??? (kidding on the last one)

At this point I would get on the internet and try to find a very very good steering and suspension specialist.

Sent from my LG G3