Rough idle, '95 Olds Ciera, 89k miles

And your engine is????

is????

roughly and goes surge-surge-surge rather than running smoothly.  It has stalled in this situation just once.  When in Park or N, or when driving 5 mph or more, the engine runs fine.  It doesn't matter whether the engi ne is warm or cold.  There is some indication that the problem is worse w hen the gas tank is less than half full, but I'm not entirely sure about th at.

you might guess, this car is only driven a few miles a day.)  The fuel f ilter was replaced at that time.

are you saying the engine idle is rough only when you step on the brake?

if this is true, I'm sure 12 guys will jump on here and tell you exactly what is the problem..

Mark

I'd suspect injectors. Get to a mech with diagnostic gear, or buy the gear. The only time I had your problem with the 2.8/3.1's a couple new injectors fixed it. But get a good diagnosis. Better to pay a good mech than to throw parts at it.

--Vic

are you saying the engine idle is rough only when you ste p on the brake?

Not just when I have my foot on the b rake. Also when I let the car "creep" in Drive with the brake off, it is often very rough.

Not rough in Park o r Neutral, though (it idles faster then).

Bad: plugs plug wires vac leak intake manifold gasket blown head gasket burned valves bad / dirty: tps maf pvc iac erg throttle body

lown head gasket

OK, in sh ort, practically everything :)

It may have been a bad batch of gasoline; the problem has diminished since getti ng a full tank from a reliable station. But I will keep looking for other problems.

roughly and goes surge-surge-surge rather than running smoothly. It has stalled in this situation just once. When in Park or N, or when driving 5 mph or more, the engine runs fine. It doesn't matter whether the engine is warm or cold. There is some indication that the problem is worse when the gas tank is less than half full, but I'm not entirely sure about that.

might guess, this car is only driven a few miles a day.) The fuel filter was replaced at that time.

How old is the gas in it? If the last time you put gas in it was 6 months ago that could be the problem or at least part of it.

-jim

Clean the inside of the throttle body and around the throttle plate and the plate itself. You should take it off to do it right. If you do it on the car, don't get any cleaner in the TPS.

in it was 6 months ago

least part of it.

Not that old. I refuel every 2 or

It wont hurt to put a bottle of good fuel conditioner in the tank. Heet was not, IMO,a really good one. It was, I believe, methanol which has limited ability to clear up wet gas.

s:DAe4l.12009$ snipped-for-privacy@bignews5.bellsouth.net...

old is the gas in it? If the last time you put gas in it was 6 months

at least part of it.

ry 2 or 3 weeks.

ood fuel conditioner in the tank.

really good one. It was, I believe, methanol

s limited ability to clear up wet gas.

What kind do yo u recommend?