Having problems with your 1992 Chevrolet K1500 ?
Idle fluxuates with ac on - 1992 Chevrolet K1500
Hi Robert, When the AC is engaged the compressor of the AC puts additional load on the engine. To compensate for this there is an up idle vacuum valve operated by an electrical solenoid. It sounds to me as if the valve is defective and cutting in and out. The valve will connected to the intake manifold via a rubber tube. I'm not familiar with your vehicle so can't tell you the exact location, but you shold be able to trace it. Regards John
The idle up valve is a valve or plunger that controls idle by steps,when higher RPM is required the plunger open more,A vacuum leak creating false air can also be responsible for idle fluctuation,
Repair Help & Product Troubleshooting for 1992 Chevrolet K1500
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