Hello. I have a 96 Chevy Lumina (car) with a 3.1 liter engine.
for the last couple months it was been hesitating.
If I start out real slow it seems to fine until I get to around 30 mph then it starts to hesitate badly then if I nearly floor it the car takes off with no problem. Now for the last couple days it has been harder to start like its deprived of fuel. There is no engine check light and no codes as if everything was fine.

Some days it can be better but for the most part this problem started off small and has gotten progressivly worse.

I changed the fuel pump & strainer, fuel filter, fuel pressure regulator, syphoned out the gas and refilled the tank at another gas station. I have also have run through a couple bottles of Techron.

Afterall this I brought it to my mechanic and he does not know what the problem is either.

Does anyone have any ideas what could be causing this or what I can try next to troubleshoot this?

Thanks in advanced. All comments are appreciated.

 

Unplug the MAF sensor, if it runs better, then replace it if not, post back. If it is the maf sensor I would think it would throw a code with CEL, but try that.

 

Thanks for the suggestion. I tried that on the the way home tonight and unfortunately the car ran the same. Of course when I unplugged it I got a 102 code so I cleared it. Thanks anyway

 

You might try some MAF cleaner, that code is what I have, it does run better unhooked. CRC has the aresol, I got mine at autozone.

 

I decided to change the MAF sensor with a new one but unfortunatly the problem did not go away. I still get a lot of hesitation.

 

You might try more injector cleaner, else it could be the throttle position sensor?

 

How do the spark plugs look? (Just the front three, the back three require you "roll the engine") Mine did that at about 200k miles, and it just needed new plugs.