Hey folks, thought I would reach out and look for some help on a problem I'm having with a 3800 99 z34 I just bought. The car had been sitting for a year and I took it out for a spin today to see how she was running. After it was good and hot after a little bit of driving It began stalling when I would come to a stop and was off the gas, the rpm 's would jump from 700-1200 and then would stall out and take a minute and a bit of throttle to fire back up and clear it self. If I remember correctly my 97 GP with the 3.8 did this when I got it a few years back and I replaced the MAF sensor and it was fine after that.

The CEL light never came on? when this happened, but I am going to see if I can take it to a buddies tonite to scan it for any codes. The fella I bought the car from mentioned something about the stalling and said something about a crank sensor but he is no mechanic and I believe he was guessing. I'm leaning more towards a bad MAF but wanted to throw this out here to see if any one has experienced this problem. Thanks in advance.

 

It could be the MAF...I had to replace the MAF on my '99 too...My wife when we were dating drove it from her house to mine (98 miles away) and as soon as we took it to the shop to have some work done to the car, the MAF went out....No warning signs nothing, it just went out. Other than the MAF, I would check the torque converter control solenoid.

 

How about a TPS?

 

Hmmm...maybe I'll just start swapping sensors from my other 3800 over one at a time till she runs right. LOL

 

TPS would cause that. Good catch.

 

Well I borrowed a scanner and had a friend who has a little bit experience with them and let him go at it. All I got from him so far was something about a yellow light being on the scanner and that there were codes pending because certain things having to do with emmissions had not cycled yet. Car seems to get hot in a hurry and I've never heard my exhaust on the 97 3800 GP get as hot snappinnand cracklin like it does on this Monte. My buddy seemed to think it was running on the lean side and that it could have something to do with the O2 sensor? Going to take the car out for a run tomorrow with the scanner hooked up to see what happens when she stalls again.

 

Well your O2 sensor will tell you if your car is running lean, but an O2 sensor won't be the cause of your car running lean. (I'm pretty sure) Ummm if it has a pending code for emissions, I might check the EGR Valve, Catalytic Converter and your O2 Sensors.

 

If it is running lean, you might be looking at a fuel pump. Have you changed the fuel filter at all? If it doesn't throw a code its usually something mechanical, but not always. And because it is stalling the way it is, not just cutting out, but fighting to stay running, i'd say its not getting enough fuel pressure. Try changing the filter, if not, you could be looking at fuel pump.

 

good call farfig.

 

Well I took the car for a run again today and didn't have any trouble with it on the road but then left it sitting in the driveway to idle and it finally got hot enough to start turning the fans on before it started to act up again. It then proceeded to stall numerous times while at idle and I was able to get it to throw a trouble code. The code it fulted for was P 0405, I'm guessing it has something to do with EGR? I am going to put a new fuel filter on it for piece of mind for the little bit of money they cost. When the car was about to stall you could here the fuel pump sound like it was working harder to deliver the proper amout of fuel to keep it from dying but yet at highway speeds with the rpm up it would not stall. Hopefully this is enough info to now narrow down the problem. Thanks for everyones help!