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Q: Misfires and low oil pressure when stopping. 2002 GMC Savana 2500

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My van is having trouble with misfiring and it also has low oil pressure at stops. The engine idles badly and when I come to a red light and have to stop, the oil pressure drops. Another problem is that the exhaust smells rich. I have replaced the distributor, cap, wires, and it also has new plugs. Please give me your diagnosis and what I need to do to get my van in a good running condition. Thanks.

A: Hey there, thanks for writing in about your...

Hey there, thanks for writing in about your 2002 GMC Savana. If you are getting misfiring, then you should have a Check Engine Light on. The light should be scanned to get the codes to see what cylinders are misfiring. Remove the affected cylinders to inspect the plugs to see if they are fouled from oil or fuel. The oil pressure drop may be due to a fuel system over rich condition like a fuel pressure regulator leak in the intake which could be causing the rich engine, running rough issue, and oil getting diluted with fuel causing low oil pressure. To have this verified, consider having a qualified pro, such as one from YourMechanic, inspect the misfiring and oil pressure problem.

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