Rough or no idle

1992 GMC TYPHOON
141,000 MILES
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GARA MOORE MORTON
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Engine has been running good, no problems. went for a drive and engine started running rough at 2000 rpm, anything above 2000 rpm runs fine. now it will not idle. tachometer jumps around below 2000 rpm. Any help would be greatly appreciated. Skip Morton, retired tune up shop owner, Thanks.
Feb 23, 2017 at 1:31 PM
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STEVE W.
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Which color combo do you have? It is the one version of the S-Series I always wanted but never could find one "reasonable" at the time.

CEL on? Fuel mileage change?

Anyway, rough idle on the 4.3 was usually the EGR sticking open from a chunk of carbon or failing diaphragm. I would think the turbo would only make that worse. The other was the IAC sticking or getting clogged.

Feb 23, 2017 at 2:49 PM
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GARA MOORE MORTON
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White with gray cladding, No check engine light or codes. I can only hope it is not the IAC that valve is really hidden. Thanks, I will let you know.
Feb 23, 2017 at 4:16 PM
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STRAILER
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Please let us know happens.

Best, Ken
Feb 26, 2017 at 12:09 PM
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GARA MOORE MORTON
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02 sensor covered with carbon, cleaned it, back to running good... replaced IAC and temp. sender with no change.. THANKS ........
Feb 26, 2017 at 10:05 PM
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STRAILER
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Nice work, we are here to help, please use 2CarPros anytime.

Best, Ken
Feb 27, 2017 at 10:31 AM