Hesitation/rough idle at stoplight

[comanche]

I have had this with two 2.4L aleros now, so I know it can't be too uncommon. When the car is in drive but completely stopped, the engine will kind of surge a little/hesitate. Maybe it's an RPM issue, but it doesn't seem to be.

Has anyone had this problem and fixed it?

[super white alero1]

Can be anything. SES light on? What code is it throwing? Check all vacuum lines, Possbly be IAC valve, IAT sensor, fouled plugs, bad TP sensor.

Does the RPM needle jump around?

[Redog]

SOunds like vacuum

[diablo]

maybe spark plugs need to be cleaned

[comanche]

RPM needle doesn't jump around... I think I'll start with replacing the plugs (using OEM AC Delco)

[PFC2]

dont bother plugs wont do anything. i have the same problem. do you have exhaust system on it. i've tried to diag it but couldnt find anything wrong. i believe its the engine trying to compansate for the loss of back pressure from the exhaust system. maybe im wrong i dont know

[comanche]

I have the OEM exhaust... and I thought maybe getting a custom exhaust would help by lowering backflow... LOL

I couldn't find any vacuum leaks.

[Oldsman]

it won't be the plugs. they would just create a miss.

it is probably a sensor and you need to have it scanned at a shop.