2002 Pontiac Grand Am Engine or Electrical

RENTERIAJOEY

MEMBER
2002 PONTIAC GRAND AM
V6
2WD
AUTOMATIC
120,000 MILES

2002 Pontiac Grand Am V6-

After the car starts it's sputters and rpms go down like it's gonna die then shoot up to 2000 then evens out. It does this like 3-4 times till it eventually evens out and idles correctly. Revving the engine a few times helps it idle faster. Also, sometimes the car starts right away, and sometimes it takes a bit longer.

Next problem is when it's finally idle and I put it in drive, I hit the gas and the car lags, the rpms are idle for a few seconds, then the rpms engage and it accelerates. It does this 2-3 times with constant pressure on the gas pedal then begins to work normally. It only happens after the car has been sitting for a few hours.

I got the car with 70000+ miles and now it has 120000+. It did have a check engine light which I had checked out were to be spark plug misfire and low coolant. My coolant reservoir, bypass hose, spark plugs, plug wires and battery have been replaced with new ones. No more check engine light but the above 2 problems persist.

Also, I noticed, when in park and idling, when I turn the wheel the rpms go down then return to normal.

I think the problem could be the alternator and/or starter. But if there is something I'm missing or I need to go have checked please let me know. I can only buy a few things at a time so if there is anyway to prevent it from failing till I purchase all the pieces, it would be appreciated! Thanks!

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

If the battery is remaining charged, I don't feel the alt or starter have anything to do with it. As far as the problem, since no new trouble codes have been set, I would start by checking to make sure the fuel pump pressure is within the manufacturer's specs and check to make sure the fuel pressure regulator is working and not leaking fuel into its vacuum supply hose. If that checks out, I would suggest checking for engine vacuum leaks and the idle air control valve (IAC). The IAC is responsible for maintaining the engine idle speed.

I noted your concern about the drop in RPM's when turning the steering when stopped and at an idle. To an extent, that is normal because you are placing an additional load on the engine. However, if it is excessive and the engine seems like it may stall, I would suggest starting your checks with the IAC. It should compensate for the added load on the engine by increasing the idle speed.