P0455 Chevrolet -

Question

I have a 2003 Chevy Silverado 1500 4x4 with the 4.8 liter engine and automatic. I ran a tank of 92 octane gas through it and the check engine light came in. It is indicating a PO455 code. The only performance issue I have found is that the valves rattle a little when the engine is cold when first accelerating. Any ideas?

Answer 1

the first thing to do for a P0455 is to try to replace your gas cap, with an OEM Chevy gas cap.

and about the rattling issue, try to use a different brand of oil. Pennzoil Ultra will give you great cold start protection