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Ivan Alvarez
Ivan Alvarez,
Category: Chevy
Satisfied Customers: 119
Experience:  lead technician at Performance Tire and Automotive
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Avalanche With Check Engine Light And Code P0303.

Customer Question

2004 Chevy Avalanche with intermittent check engine light and code P0303
I have changed wires, plugs and swapped coil packs. The engine oil has been flushed and changed. Fuel injector cleaners. Car has completed 168,000 miles.
#3 plug seemed like it was cross-threaded when installed. Removed reinstalled and tightened. Felt not leaks or blow by when engine was running. Ticking noise from the area of 3 cyl both before and after.
What more can be done?
Submitted: 4 months ago.
Category: Chevy
Expert:  Ivan Alvarez replied 4 months ago.

Have you checked compression?

Customer: replied 4 months ago.
Not yet. Does not seem like there is a miss
Customer: replied 4 months ago.
Will test and get back with you
Expert:  Ivan Alvarez replied 4 months ago.

Ok. Do regular cranking compression and running compression if possible. Usually if there is a problem it will show up under a running compression test. The ticking noise may possibly be a bad lifter. These engines do have a problem with the lifters and when it gets bad enough it can damage the cam. I have done a few that don't have a hard miss just idle a little rough.

Customer: replied 4 months ago.
Ok sounds good. Won't be able to do anything till the weekend. Will reply here. And thank you.
Expert:  Ivan Alvarez replied 4 months ago.

No problem.