It started last night driving home from VIR. The car just started stumbling and missing and coughing. I pull into a gas station and it just dies. It starts back up but won't idle for sh!t. Upon closer inspection with the hood up, something is telling the fuel injectors to send every bit of fuel they can to the engine. I can hear them straining. The car is running so rich, a cloud of unburned fuel from my exhaust envelopes the gas station.

Here's the really REALLY weird part. I turn off the fog lights, and the car runs perfectly. Turn them back on, and it runs like sh!t. Off, great. On, sh!t.


I am at a complete loss. Clues? Anyone?

if it doesnt sound like a broken record....probaly the MAF. Sounds like there is a short that is caused by the fogs that is shorting out the MAF making it go into limp mode. I bet a reground might help. Worth a try

I have done a reground on the MAF, but I will check it. Anyone else have a suggestion?

I didn't think limp mode made it go that rich. Even if it is limp mode, a MAF problem shouldn't be fixed by turning the fog lights off.

I'd just follow the fog light wiring and grounds. See what you can find.

Hi Matt, lets see if I can help;

Okay so when the fogs are on you run rich. When they are off everything is okay. right? If that is the case then it seems to me that the problem must be in the wiring of your fog lamps. Could you have a short to your injectors that when you turn on the fogs, you're sending more juice to your injectors? Hence they're sparying more gas. Have you not noticed this problem before? I mean do you never run your fogs? Therefore just now noticed it? I would grab a volt meter and check your voltage to your injectors with the fogs off, then turn them on and check again. If you see there is higher voltage when the fogs are on there is your problem. Then all you have to do is find out where their paths are crossing.

Just a thought, hope it helps.

I generally run my fog light all the time. I had them on (lights and fog lights) leaving VIR on Saturday. About 3 minutes into my trip home, the car just started running like shit. All of a sudden.

I too suspect the fog light ground. Although I cannot for the life of me figure out why a busted ground on the fog lights would do this.

It sounds as if your MAF is being shorted out somewhere. Check to make sure you don't have wires crossed somewhere. Where is your MAF regrounded to anyway?

Weird, I just ran into a similar problem a few days ago..... turned out the harness that grounds the MAF was loose and the chassis ground had some corrosion on it. now I must ground the maf to some other location since the factory harness no longer works (short), but it runs just fine.