Thread: 2000 Grand Prix 3800 Part Throttle SURGE trans???

I have gotten a lot of help with my/my wife's 2000 Pontiac Grand Prix GT at LS1. I posted my latest question there as follows...


I got a 2000 Pontiac Grand Prix that you guys have helped A LOT on, THANKS ! ! !
When the wife used to drive it it was diagnosed as having trans issues.
A couple shops said it needed to be rebuilt w/o even seeing it.
Another shop scanned the computer and said solenoids in the trans were sticking.
Those were replaced and it seemed fine for last 30,000 miles. It has over 180,000 on it now.
We have owned it since new though and had a pretty pamapered life.
But when I drive it now, it seems like it does not drop out of OD like I would expect it to.
If it were an old school carb motor and auto, I would think that was the case, or the lock up convertor was not releasing, but that is my old school likeness...
But when I am trying to accelerate or head up a hill at around 2500 rpms say, the tach will start to stary from 2200 to 2800 and the car kind of lugs and surges. Trying to describe as best I can.
About a year and a half ago I cleaned the mass air sensor, replaced the oxygen sensors, and ended up replacing the cat which fixed the SES light and it has ran realy good until now. If anyone thinks anyone of that is related at all, sorry if not. No light now, just the surging. I just give it a lil' more gas, stand on it harder and it takes off revs a lil' higher and all good.

Appreciate any ideas, known issues, or similar scenarios...THANKS again ! ! !



I got this reply, sooo
HERE I AM

Sounds like torque converter lockup solenoid is messed up. I have a 98 and it does the same thing. Go and check out grandprixforums.net There is a world of info on that site, and almost everyone on there has had that prob with there car.

Now I am off to the intro section.
THANKS in advance!

Well I have been reading through all the tcc solenoid issue threads.
Planing on shorting the battery cables to clear the codes, maybe spray and clean the MAF, check for vacuum leaks, and see what happens. I am thinking about dropping 1/2 can of SeaFoam TransMedic in if the surging persists. I had tried that about 30,000 miles ago before trans shop dropped trans and replaced solenoids. I am not sure if they did the TCC one then or not. Before that I had dropped the pan and replaced fluid and filter. The magnet was barely hanging onto a very lil' film of fuzz. Even with the miles fluid has always been nice, red, clean. Still is. Just getting the surge, flutter symptom.
Anything else I might be missing?
IF I do end up back at trans shop, anything I should make them aware of?
THANKS!!!!

I had a bunch of water in my trans causing 4th to slip and surge like that... Probably need a rebuild if you dont have water in your transfluid.

No H2O in the fluid. I did the crossing the battery cable/code clearing deal, tossed 1/2 can of TransMedic SeaFoam in there and just about the same if not slightly worse. I am going to dig out my receipt from the trans shop and see if they did the TCC solenoid, give 'em a call, and see about getting it scanned at least. Doesn't sound like there is anything else to try or do w/o dropping the trans....is there?
THANKS AGAIN!

Looked like it was my MAF sensor.
Ran through my progession of investigation and repair on LS1.com.
If interested, here's the thread

2000 Grand Prix 3800 Part Throttle SURGE trans??? - Page 2

I was glad that the transmission shop I dealt with was upfront and honest.
I know an awful lot in my area just replied that the trans is a common issue and needs to be rebulit for a few thousand dollars. $68 MAF sensor from Ebay makes me much happier.

The trans in this car was "rebuilt" at the dealer when it had less than 20,000 miles on it. Warrantied. No idea if they did any upgrades or updates then or not. About a year and a half ago it started acting up. pressure regulating solenoid was sticking. I changed fluid and filter then, everything was like new. The lil' magnet in the pan had barely a film of slime on it. I had a real hard time believing MANY trans shops that said it was junk and needed total rebuild. Finally one shop scanned it, test drove, and said the solenoids could be replaced and maybe all would be fine. I think it was $350 or $400 for those. That was about a year and a half and 50,000 miles ago. I was fearing this would be the end of the trans now, but got lucky. PLENTY of scamming tranny shops that I know about now though!!!!

I call it scam because... (ya ready?)
2 shops diagnosed over the phone w/o seeing car, threw out $2000 estimates (with payment plans if I needed), and started pushing to set appointment so they could get started. Another friend of a friend was going to give me the "buddy" deal on just replacing the solenoids. Co-worker had know this guy and used him for years. Work was going to be done after hours to save even more $$$. For $250 the trans was to be dropped and solenoids replaced, just like what I ended up having done. Drove the car 15 miles to shop and it ran fine. Get home and there is a message on the phone saying the entire trans needs rebuild and the car will not even move from where I parked it. Tranny just gave up the second I got out of the car. Sounded way too fishy after his price went near $2000 too. Drove from his shop to the one that ended up doing the work. Car ran and drove fine for me then. New solenoids have kept it going for past 50k miles and a year and a half now, still going
Atleast a dozen shops would have rebuilt trans at a pretty price. May have been lack of knowledge rather than trying to be a rip off in a few cases, but some were blatanat and obvious. Liek anything else, buyer beware. I know that there are good and bad shops, I feel like I had found an honest and trustworthy one that I ended up going with, and have been thankful for them. They even scanned the car for me a couple weeks ago when the surge got too terrible. But anyways, my saga has another chapter...here's what I posted this morning on LS1.com...maybe it will mirror something somebody else has been through or may see sooner or later...

DARN IT!!
Thought I had it made yesterday. Car runs GREAT. Much better throttle response. I like it!!
BUT after about 200 miles of driving, the SERVICE ENGINE SOON light lit again
Went to Autozone and got it scanned. I was told it showed P0171.
Said the front bank of cylinders was showing a lean condition.
Said that it could be MAF sensor, fuel pressure, O2 sensor, ignition misfire, or fuel injector trouble...
Wondering what is best to do next????
I never thought that there was an O2 sensor per bank, I had replaced the rear near firewall and the downstream one.
The front one (which I never even noticed before and it was never mentioned, but I guess if it can throw codes specific to front and/or rear there must be 2) is original to the car.
Wondering if un hooking battery, touching positive and negative cables together and doing that "reset" is worthwhile or not...?
Good or bad idea? Would doing this help clear trouble codes or get things back on track?
OR does it sound like there is another real trouble...?
MAF sensor (NEW) suspect? I am thinking that both front and rear codes would show then, right?
AGAIN THANKS ! ! !

Quite a list there...
I saw a lot about the vacuum tubes and their connectors there.
I take it that there is no front )2 sensor then?
I have played with the formed vacuum hoses and the connectors by the throttle body when I was getting an EVAP error. Actually had a broken one that I had "crazy glued" back together. Maybe time for that again...? Or some new pieces.

Is that what you meant by easy?
THANKS ! !

I did just pull the "T" off near the throttle body.
I think that (or gas cap, never really knew for sure) was giving me my EVAP code..before

I did not see (probably just did not look hard enough yet) to see if there was a good source for these.
Dealer?
Elsewheres?

BIG Thanks !!

Well...the SES light has come and gone. Twice scanned, same code now.
Looked over all my possibilities. The hoses and lines seem to be good, or at least same as they have been for nearly a year. Contacted my Ebay seller of the MAF sensor...got this response when I reported my troubles since installing their part...

"We introduced this product this month, and your part is the first to fail out of few dozens we sold. It's really a small sample to draw any conclusions. We will mail you a replacement by this afternoon, along with a prepaid label to return the defective unit."

Did not think I could ask for any better response than that. I started thinking that even though the car ran crappy with it's surging, it did not have the SES light on until the new sensor. I will try another one like this and see if it persists. I then asked seller,
"Will the new one have different calibration or specs?
I see that you also have refurbished units. Do these have a better track record?"

Just in case the next one does same due too it's design, specs, or whatever.
Wondered if a different sensor would be needed...got this:

"The refurbished ones are on back order. I don't think we have had any issues with these.

We sent you a replacement with a returned label. If it doesn't function as it's supposed to, I can get you an estimated delivery date for the refurbished ones, and see if we could get you a good deal on a brand new unit through our supplies.

Seems like they are being as helpful as can be. Hoping that sooner or later a different MAF sensor fixes all of this

I did not initially un hook the battery when I swapped the sensors, but a few times since I have un hooked the terminals in order to clear codes. The second time I crossed the cables. I am not 100% sure that there is not another possibility, and I cannot say everything was 100% fine beforehand, but no SES light until the new sensor. That was the one thing different. I keep thinking that things will adjust to the new sensor, but I am hoping that the fact there was only one variable introduced and that was the sensor. Again, HOPE that is it, fingers crossed. I have not quit looking for other issues, but have not seen anything else suspect so far.