Questions and Answers

Saturn SC1 Coupe Idle Speed Concerns Q. Dear Sir, I have a 1996 Saturn SC1 Coupe with a 1.9 liter four cylinder DOHC engine with 120,000 miles on the car. It seems to idle rather low when in gear, especially in reverse. According to the RPM gage, it is just barely over 600 rpm, which is where, according to the manual, it should be, between 600 to 700 rpm.

It idles a little higher when running the A/C but it still feels a little shaky. The car jerks a little when braking due to the idle. It isn't a worn brake pad type of braking. It also threatens to stall a little at times when accelerating. It won't quite lose power, but it will give jerky acceleration if I press the gas lightly.

According to the manual, it has a computer controlled idle that "should not need adjustment." I do not see any sign of a vacuum leak, and the EGR valve was recently replaced. I just changed the spark plugs and wires, and it cranks up beautifully, so I know it likely isn't the ignition system components causing the trouble.

Could it be a clogged fuel filter? I haven't noticed a considerable problem with general accelerating all the time, just when starting off from a stop. It idles perfectly fine when in park or neutral. When the A/C is running, it idles at around 900 rpm and without, around 800 rpm while in park, but it doesn't sound or feel like it is too high.

It appears to be just right when in park and in neutral. Could I just be over-reacting or could this be a sign of a serious problem if left unchecked.

A. This does not sound like a serious problem to me. If it really bothers you, take it to a dealer and have them run some tests on the Idle Air Control (IAC) motor and see if there is a cleaning procedure that may help.