2003 silverado 5.3l misfires and electrical issues.

[wj03049]

I've been dealing with misfires in my truck for about 2 years now. Initially I had a p0300 random multiple cylnder misfire, flashing CEL, the truck was very shaky from the misfiring. I had all the spark plugs and ignition coils replaced. That solved the misfiring temporarily. Then I started getting the flashing CEL and p0300 again intermittently, it would only last a few seconds and the truck drove normally, I took it to a shop and they couldn't find a cause for the code and it wasn't misfiring all the time.

 

Eventually the flashing CEL came back consistently with a slight loss of power, I had a p0352. Replaced the ignition coil on cylnder 2 and it went away. The next week I had a p0304, replaced the ignition coil and it went away. Now I have a p0308. So it seems I'm burning up my ignition coils

 

Other issues with the truck are codes p0175 and p0172, system too rich bank 1 and bank 2. The voltmeter dips low and then jumps high when I'm turning at low rpms and the truck frequently stalls when I'm turning in parking lots, usually when it's still cold.

 

I'm thinking the electrical issue is causing the coils to go bad. Anyone encounter anything similar to this?

Edited November 28, 2023 by wj03049

[richard wysong]

More than likely it's just the coils failing 1 at a time. Voltage spike shouldn't damage them but definitely not good for the puter

[richard wysong]

What would damage the coils is worn out spark plugs/ bad wires