Unsullied_Spy

I have an '02 Mustang GT that will start and idle fine, but if I give it any throttle it stalls. It just started doing this after pulling the alternator off to replace it, and had the same issue trying to run without the alternator.

mustang_pa

clean or replace your maf (mass air flow sensor). That is where i would start. Are you driving when it stalls or just reving it up? You can also replace you TPS (throttle position sensor) or IAC (Idle air Control). I don't think that it would be your IAC just because it idles fine and just die when giving it some throttle. I know there is a very easy test you can do to make sure you TPS is working right, i just can't remember what it is, it has be so long since i have had to do it.

Unsullied_Spy

I pulled and cleaned the MAF and tried again but still no good. It starts up and then the RPMs drop to basically stall but I guess there's enough rotating mass left in the engine that 1 cylinder can still fire and it picks back up and revs to 1,300 or so then dips back down and after a few seconds it steadies out and idles perfectly. If I give it light throttle it dies immediately, if I jab at the throttle it sputters, backfires, then revs. I'm going to have a mechanic come out to look at it tomorrow, backfiring with a plastic intake manifold is no good.

FYI: I can definitely smell that it's running rich so I'm thinking it's something electrical that sends a signal to the ECU to adjust the AFR. Right now the TPS seems likely but also maybe an o2 sensor. I'll see what my mechanic thinks when he looks at it.

X6StringerX

Please post back when you solve this. Mine does almost the same exact thing and I don't have any SES codes. The only thing that is different is that mine doesn't idle down quite as much as your's... mine stays at least above 500, but bogs when I give it any kind of throttle and if I try to go WOT, it'll rev slightly and backfire. After a couple of minutes, it runs fine... only does this when it's cold. I Seafoamed it last week and changed the plugs and that didn't seem to improve it at all. I'm about to go clean the IAC right now to see if that'll fix it.

X6StringerX

Ok, I went out to clean my IAC and it started pouring the rain. I had to wait a couple hours, but was finally able to remove it, clean it, and reinstall it. It only took about 20 minutes. I read on the forum that you should let the car run for a couple minutes after reinstalling it to ensure that all of the carburator cleaner and gunk works its way out of the IAC. It still acts just like it did.

To OP: Please update this thread if you figure out what the problem is. I suspect I'll need to replace or clean the same part.

DreamerGT

how many miles is on the car maybe the o2 sensors are going bad.

X6StringerX

I don't mean to thread jack, but I thought this would be acceptable since we are both experiencing almost the same problems. If you're asking me, my car is a '00 with 66k.

Wouldn't a bad O2 sensor throw a code?

Unsullied_Spy

Mine's at ~98,500.

X6StringerX

Here's an update with all the things I've tried so far. None of them have worked.

Seafoam
New Plugs
Clean IAC
Clean MAF
New Fuel Filter

It looks like the TPS is next on the list.

98blackArt

My car was experiencing the same thing. My car would start and then it would die. I could get it to run on idle for awhile but once i reved it the Rpms dropped and it died. So i changed the IAC valve. Nothing happened. So i changed out the fuel filter and nothing happened, then I changed the fuel pump and it started like a champ.