2000 Silverado 1500 LT 5.3L Engine Fault Codes P0155, P0302, P0327, and P0430 - Power Loss When Pulling Trailer
My 2000 Chevrolet Silverado 1500 LT with a 5.3L V8 engine is showing fault codes P0155, P0302, P0327, and P0430. The truck starts smoothly and runs well under normal conditions, but I experience noticeable power loss when pulling a trailer—no 'get-up-and-go' performance without the trailer. I've already replaced both knock sensors twice, and the catalytic converters are installed. The muffler was removed and replaced with dual straight pipes from a 'Y' pipe setup, which I had when I originally purchased the truck. This modification has always been present, and it's been associated with the P0155 code since then. The other codes (P0302, P0327, P0430) are newer. Given this history, what should I check first to diagnose these issues? Is there a connection between the exhaust modifications and the performance loss or misfire codes?
Refer to common causes and solutions for these trouble codes in our forum. Start with diagnosing P0155, followed by P0302. The P0430 code may indicate failing catalytic converters—check exhaust back pressure, as elevated pressure can contribute to reduced engine power and misfires.