I have a 2001 silverado with the 4.8l its my work truck but i have done a few changes but nothing big ( headers, cold air and a throtle body spacer. In the last month i have been getting an error code saying that im missfireing and i cant figure out whats doing it. So far i have done plugs wires. this only happens when i hit about 4100 rpm. So now im stuck and GM know nothing so i look to you guys.

 

someone had a similiar problem if you read a thread at https://ls1tech.com/forums/showthrea...ght=error+code You dont have a lot of mods so hopefully your just getting a false reading and need a tune. good luck