My car currently dies, or major hesitation when I stomp on the gas. If I gradually press the gas pedal it will run and maintain rpm's.

I have codes P0171 and P0174(I have does CF searches running down the same troubleshooting steps with no result), below are a list of things that I have recently.

New Fuel Pump (previous issue, car would not even start)
New Fuel filter
New O2 Sensor(Drivers side exhaust)
New Fuel Pressure Regulator(not a fun project) had to remove fuel rail.

If I disconnect the MAF it runs like crap(someone suggested it as a troubleshooting step)(apparently the MAF is working

CheckerAuto tech thinks is it the Throttle Position Sensor. I would expect it would throw a code if the TPS was the issue.

Thoughts?
Thanks for any other ideas!

--CastleRockCamaro

 

Did you clean the MAF sensor when you removed it? If not you might wanna try that, if that doesn't work check for a possible vacuum leak after the MAF sensor.

 

I was able to clean the MAF since I had it out while replacing the Fuel Pressure Regulator.

I sprayed Carb and Choke cleaner around the MAF and each side of the Fuel rail and no change was noticed. So no leaking.

 

PCM is complaining about a lean condition.
Possibilities:
Low fuel pressure. Have you checked the fuel pressure after replacing pump & regulator?
Injector/s not getting fired. Check with NOID lites.
Clogged injector/s. Try injector cleaner.
Bad O2 sensor. Check activity of both sensors with scan tool.
Air leak between MAF & Trottle body
Bad ECT sensor. Check coolant temp with scan tool, it should be close to temp gage.
PVC valve stuck open
EGR valve stuck open

A bad TPS will cause stumble on fast throttle opening, but will not cause a lean condition.

 

Wonders what the right tool will find! Fuel Pressure gauge was at 12psi. Fuel was leaking just out of the fuel pump inside the tank, the rubber fuel line was loose. Replaced the rubber fuel line and now about 55-60psi. I was amazed the car actually ran with only 12psi. I drove it back and forth to work running with low fuel pressure yesterday for 45 miles.

Thanks again for the posts.

CastleRockCamaro

 

Get it started and the fuel will siphon itself out even with a leak in the hose :P It will miss like crazy if you stomp it and if the leak it too much, it will die quite often.