Anthony Womack

My car has been having problems for a few months now. It all began when i changed the front three spark plugs (had a mechanic change the back at a later date) and the pcv valve. When changing the pcv valcr I broke the vacuum hose and used fuel injection hose to replace it. Also got the catalytic converter straight-piped, fuel filter replaced, egr valve replaced, idle air control cleaned a bit, mass air flow cleaned, and throttle body cleaned. Although the problem changed from the car stalling when in idle and in park to just idling at a stop sign, it is still stalling and hesitating upon acceleration also. It starts up fine and seems to run fine until attmepting to accelerate a bit or at stop signs when it will begin to somewhat bog down until it stalls. Can anyone help me or give any advice?

Frank3

Have you checked the pressure on the fuel rail? I had similar problems on my 2001 Impala with the 3.8L V6. The fuel pressure regulator was bad. I had put a gauge on the rail monitored the pressure and watched to see if it held pressure after shutting off the fuel pump. If I recall correctly, I think after the fuel pump shuts off there was supposed to be LESS that a 5 PSI drop in the rail over the course of an elapsed minute after the pump went off.
Mine had low pressure when the pump was running and immediately dropped to zero when the pump stopped. By putting a test adapter on the fuel return line, and gradually closing it while monitoring the rail pressure, the pressure came up to what it was supposed to be and it held the pressure after the pump shut off. A new fuel pressure regulator did the trick for me.

Check in a service manual for your impala to get the proper test procedure for it.

Good Luck!

Anthony Womack

i just replaced th fuel pressure regulator as, if nothing else, it was leaking pretty badly. Hopefully this does the trick. Thank you for the input!