Thread: Car runs badly and almost stalls

Hi everyone. I have a 2000 Grand Prix GTP and I'm having issues.

I have the P0452 and P0171 engine codes. Here's what I did recently:
- Replaced MAF a week ago
- Replaced filler hose between filler neck and gas tank a week ago
- Ran new fuel line from tank to engine a week ago
- Gas tank, filler neck and fuel pump replaced last year

Currently idles up and down and almost stalls in park, neutral and drive at a red light. RPM's jump from 1000 down to 200 constantly. If I unplug the MAF, the car idles fine.

I also have an electrical issue that may be related. I blew the fuse to the lighter. When I replaced the fuse the lighter still didn't work. I've checked all the grounds in the engine except for the one on the starter. Heat will come out the drivers side when the temp is down to 15. Sometimes heat won't come out the drivers side and only the passenger side.

Just a note too that my valve cover gaskets do leak. Could the oil have leaked on a sensor or something that might be causing these issues? They only seem to leak when I'm going up or downhill. Yes, I know I need to replace them ASAP.

I'm wondering if I am having bad electrical issues??? If so, can anyone point me where I should start looking? I've been looking and checking many wires to date but haven't found any corroded or broken ones yet. If anyone can give me some insight on where to start looking I would greatly appreacite it. Thanks in advance!

The P0452 is Evaporative Emission Control System Pressure Sensor Low Input. P0171 is System Too Lean (Bank 1)
I will have to check more for vacuum leaks. Haven't found any yet. I'll change the PCV too. Last time I just cleaned it because my parts store didn't have one for my car.

And, I also took out my IAC and cleaned it with sensor cleaner. Didn't make a difference, but at least it's clean now.

So if you unplug the MAF and then start the car it idles fine? In gear and in park/neutral? You could test drive with the MAF disconnected once the car "learns" to run on the preprogrammed tables w/o the MAF. Just don't beat on it or drive for a long time this way. Double check the wiring to the MAF as it is known to be suspect.

Beyond that you could have a bad MAF. A lot of failures of aftermarket MAF's have been noted, even out of the box. Usually people end up getting a genuine OEM one from GM or a parts car somewhere.

Well, 2 bad MAF's is possible I guess. It still throws the P0452 code and even if I clear it, it comes back right away. With the MAF plugged in, it's doing the exact same thing as with the old MAF. However, the car worked perfect after I put the new MAF in. It just started sputtering recently. I'll check the MAF wiring too.

Have u checked fuel pressure at the rail?


~ : Andrea : ~
2008 GP @>~~\~~~
Aka Charlotte