Mechanics

DIESELING UNDER LAD

1999 Chevrolet Other • 200,000 miles

Changed plugs, wires, cap, rotor. Fuel pressure is 55pds. The engine still does this dieseling under load.
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Hondaguy
August 30, 2011.



Try up grading your fuel it might help. One more thing hook a scaner to it and make sure it dont have any egr codes

What is model of vehicle, litre size of engine? If you have preignition, can be caused by a hot spot. I thought dieseling was with the key off? Check compression.

JDL
Aug 30, 2011.
Most newer cars have spark knock under control, unless it has a vac leak or a fuel, or egr flow issue.