Miss at idle; IAC?
Thread Starter
Racer
Joined: Apr 2001
Posts: 302
Likes: 0
From: South Haven Michigan
Miss at idle; IAC?
I have an 89 Convertible with a completely stock L98 engine/auto trans that has a miss at idle when in gear (600 rpm warmed up). You can't really hear it, but I definitely feel it when I am sitting in the car. When not in gear, it isn't quite as noticable (700 rpm warmed up). When under cruise or acceleration, I don't detect it at all. It seems to be getting worse the last few weeks, not sure if the colder than usual weather has anything to do with it or not.
The SES light has never come on, but I checked for codes anyway and there are none. I only drive the car 800-1000 miles a year. The AC plugs are 6 years old, the Accel cap & rotor and AC wires about 3-years old. I did a physical inspection of the wires, didn't find anything, all are still tight on the terminals.
I cleaned the throttle body a year or two ago still on the car as good as I could using TB cleaner. I didn't touch the IAC or TPS.
Could the IAC be causing this?
The SES light has never come on, but I checked for codes anyway and there are none. I only drive the car 800-1000 miles a year. The AC plugs are 6 years old, the Accel cap & rotor and AC wires about 3-years old. I did a physical inspection of the wires, didn't find anything, all are still tight on the terminals.
I cleaned the throttle body a year or two ago still on the car as good as I could using TB cleaner. I didn't touch the IAC or TPS.
Could the IAC be causing this?
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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Sounds like spark plug wire(s) arcing to me. Open the hood of the car at night or in a darkened garage and look for telltale dancing sparks across your ignition and plug wires.
When you do a tune-up, one of the things you replace on your engine is the cap and rotor -- these eventually wear out because of the arcing.
Also, the spark-plug wires eventually wear out and lose some of their electrical insulation. This can be the cause of some very mysterious engine problems like you're describing.
When you do a tune-up, one of the things you replace on your engine is the cap and rotor -- these eventually wear out because of the arcing.
Also, the spark-plug wires eventually wear out and lose some of their electrical insulation. This can be the cause of some very mysterious engine problems like you're describing.
