Thread: 98 GP GT 3800 with P0171 off and on?

Did you resolve your issue Fritcr? I just picked up this code about 3 weeks ago myself. Thoroughly cleaned out the throttle body and the MAF sensor with their appropriate cleaning sprays, and have been good for about two weeks but now I picked up the exact same symptoms you have along with the code again. Idle was kind of funny for a few weeks but since the temperatures started dropping here in New York around the same time, I chalked it up to the cold weather starts but its really freaking me out now. Car was doing so well since doing the LIM gasket this summer too...

I just went though all this with my GP and it turned out to be UIM

What did you replace you UIM with? The zzp kit? I'm about to tear into my UIM fully expecting a flood of coolant beneath it. My fiancee now tells me that she has been hearing a "water sloshing/gurgling" sound when the engine was cold. Weird how I didn't notice that. Time for a manifold massacre... in 28 degree weather

Update: Definitely time for a new upper. Warpage along its throttle body connection and see gooey leakage seeping between the bottom of the upper intake manifold and the top of the upper intake gasket. Not worth ripping apart the engine to take thorough look without having the replacement parts to throw in at the same time. To damn cold. Hopefully I can get a UIM solution via UPS asap.

I did mine with a dorman from advance auto. I needed it fixed fast and didnt have to wait. I also have the water ports on the LIM filled to

Buy Dorman - OE Solutions Engine Intake Manifold 615-180 at Advance Auto Parts

@Fritcr: Still haven't torn into the engine as I want to wait until I have the replacement in hand but im about 90% sure that's the culprit of my p0171. Will update you as soon as I get the new parts but I didn't want to leave your other questions unanswered. I tore through the engine to do the lower intake during the summer so working in the upper intake is literally half the job. It took me about 10 hours to get everything off but that's because I cleaned everything as I pulled it off. Absolutely not hard to replace the lower, just tedious and requires patience. So long as you take your time and pay attention, its almost foolproof. Anyone mildly "wrench" inclined can do it and since we're really focusing on the upper, its really not that bad.

When I did the LIM, I used three resources:
1. Here for torque specs to re-tighten all the goodies

2. I printed the step by step instructions from here (There are videos attached to this site and they do come in handy for in depth analysis but I found the below video more concise. I also recommend reading the comments on here, lots of useful info. especially this comment click me

3. Watched this video on my laptop as I worked on the car (recommend watching it a few times before you tear into the engine so you aren't in the wilderness. Its helpful to download it to your computer so you can watch it offline. Oh yeah, the vid is using a GTP so it doesn't have the upper intake manifold removal instructions but it shows you all the other stuff you need to remove before you can even get to the supercharger or in our case, Upper intake Plenum. After that, you can just do the step by step instructions in link 2 if you aren't going to touch the lim)

Again, even though all these instructions were used for the lower gasket, you need to go through the upper on the way down. Mind you there are more sites I used since this was really my first time digging into an engine of any kind but depending on how familiar you are with the car, you may be able to figure out whats what. I don't really have much info about the thermostat because I haven't even touched mine. I've driven this car almost 10,000 miles in the 3 years I've owned it and have been taking repairs and upgrades one day at a time. Basically, if it ain't broke, I don't fix it.. or touch it.. or breathe near it, if I can help it. And unfortunately, I don't know for sure if it will fix the p0171. Yours or mine. Its just one possibility of many. I took apart throttle body and MAF sensor to clean both since that was the easiest fix for this code. Then code came back with a vengeance about a week later. Now my car struggles to stay on. I just weigh my odds based on deduction and experience. In my case I saw some leakage coming from the upper intake gasket area under the throttle body. I know for a fact the lim is good because I put it in there myself and I took my time to make sure it was done right. Plus I didn't see any signs that the lim failed (oil in coolant or vice versa). Its a reasonable deduction in my case that the upper is leaking and if it's leaking air, odds are good its leaking fluid too. I've only had the car for 10,000 miles out of its 204,000 mile lifetime. As far as I know, the upper may never have been replaced or serviced. The way I think about it is.. I know for sure the parts I put in my car are new and are installed correctly so if the code doesn't clear after doing all this work, at the very least I have one more possible cause of the code to check off the list and I wont have to worry about the uim or gasket for (hopefully) a long time. Its all an investment anyway, right?

@grandamle1: Thanks for the link. That's the one I was looking at too but was planning to order it from zzp. Only problem is the don't say which model they are selling so I didn't know if they just had the upper intake with gasket or the one with the gaskets and stuff. I know that the 615-180 has all the extra goodies attached so was gonna hunt that down before I bit on the zzp. Got lucky and found it on Amaz*n with free two day shipping for ~80 bucks. Thank god for amaz*n Prime.

PS. @Fritcr: If you do decide to get the upper intake, Amaz*n has it here for a really good price

PPS. Found pictures of the LIM job... not really helpful since we're talking about the upper here, but figured I'd mention it in case you want to see the damaged gasket and the horrible cholesterol that made the job take so damn long. Its amazing how much damage can be done due to these things not being taken care of.

Your welcome, when you go to put the brake booster hose back lube the o-ring really good and make sure it stays in it groove. mine kept sliding back. As far as putting the UIM in i had it done in 30mins