For the last couple weeks I have noticed that when I gave my car gas it would sort of chug and then take off alright. If I lightly applied the accelerator it would be fine but whenever I would tromp the gas it would stumble... at any rpm. I thought it somewhat strange, but didn't have time to get it checked out. I went on a shopping trip about 30mins from home. It drove fine all the way there except for the previously mentioned stumble. After being in the store 15 - 20 mins I came out and started the car. It cranked fine, but when it started it was idling terrible (around 600- rpms) I gave it some gas and it promptly sputtered down and died. I tried to start it a couple times with the same results. Anyway I got it towed to a shop near my home and they said it needed a new fuel pump. So I ordered a new fuel pump and fuel filter. They put that on with no change in the symptoms. Actually right after they put the fuel pump on it started alright and ran for a little bit and then all of a sudden reverted to the bad idle and dieing when given gas. I am at a loss of what to do. I was wondering if the fuel pressure regulator could be the problem? If so, is there a way I could test it myself? My Haynes manuel mentioned something about clamping the fuel pressure line to increase pressure. Any help you all could provide would be greatly appreciated.

 

Check the tracks on AFM. They are probably worn. If so when you give it gas trap door opens, but loses signal to DME so the DME shuts off the fuel.

There is write up of this on Fr wilk site

 

That is one place to look, and from the symptoms, most likely. However it could be the pressure damper/regulators. I do not know how to diagnos or test those, I just replace them. What part of the country are you in? I have a spare AFM and could give you a hand if you are in the area.

 

This is what mine was doing as well, except it would idle around 800rpm and didnt sound like a perfect idle, then when given gas it would promptly die. And now wont start at all!?!

 

That sounds like a TPS. I have had the same problem, fixed with a new TPS. A quick way to check is simply unplug the TPS. Leave it unplugged and drive a bit. The DME should run in 'safe mode', full rich and 1.2BAR (if you got a turbo).

Easy to check at least.