I have a 2002 Buick Century. ( 3.1 engine )
Suddenly, I've got a rough idle ( used to be silent ) and a "stumble" when accelerating from a stop.
In the old days, I wopuld have looked at vacuum advance.
Today I'm guessing at; bad sparkplug bad plug wire blocked/defective fuel injector.
Any way to isolate this ?
To that list add, dirty fuel injectors, bad throttle position switch, bad oxygen sensor, bad AIC valve, dirty throttle body and so an and so on. I would recommend first getting the computer scanned for possible fault codes.
Brian
I'd guess it's a spark plug or wire. There's likely a misfire code that's been set, if you can read the trouble codes out it will probably help narrow it down.
It's real common on these engines for the plug wires to go south. I would pull the wire ends off at the coil packs and see if any of them appear to have corrosion at the coil pack towers. You will often see a rusted, corroded tower. It it's bad enough, you will need to replace the coil itself.
Ian
Is the idle only rough when first started, and when sitting in traffic when up to temps in gear?
Charles
Usually after it's up to temp....
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