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1991 Cadillac DeVille 4.9L Poor Idle Quality
Posted to GM Driveability on 7/19/2001 15 Replies

idles and runs normal with ac off. turn it on and idle gets rough, spark knock occurrs, hesitation, miss under load. turn ac off, problem goes away. have cleaned throttle & egr & passages, replaced egr solenoid. still works the same. almost like ac relay is sh...

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car Vehicle Data

1991 Cadillac DeVille

VIN 1F6CD53B1M
Engine4.9 L / 8 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsUS
SymptomsPoor Idle Quality
Message Closed w/FIX

car Vehicle Data

1991 Cadillac DeVille

VIN 1F6CD53B1M
Engine4.9 L / 8 cyl / GAS
Trans4-speed Automatic (Electronic)
DeliveryFI
EmissionsUS
SymptomsPoor Idle Quality