1993 Chevy Silverado 1500 4X4

KELLYGIRL

MEMBER
1993 CHEVROLET SILVERADO
V8
2WD
AUTOMATIC

My 1993 chev silverado 1500 4x4 has an issue; 1. It revs up (while driving) to cause transmission to drop a gear 2. The idle will fluctuate (while in gear and stopped) and stall 3. While stopped (in gear) truck will surge forward 4. Service engine light will come on most of the time when these issues happen 5. Does not to it all the time but getting more frequent 6. When issue occur the odometer stops working 7. Acceleration is slow when idle engine light is on (during the mentioned issues) 8. New computer was installed it ran smooth and strong for 45 minutes, then back to problems 9. When I take it in there are no trouble codes - the issue are intermittent

Monday, August 15th, 2011 AT 6:03 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

The computer needs scanned when the light is on. It sounds like a combination of a bad idle air control valve and throttle position sensor. However, that is only an educated guess without trouble codes. Check for simple things too such as vacuum leaks. When the light is on, take it to a parts store, don't shut the engine so the light stays on, and ask them to quickly scan the computer. If you can't do that, you need to have a mechanic drive the vehicle with a live scanner so it documents what is happening while it happens.

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Monday, September 5th, 2011 AT 4:42 AM