Hey All,
I've looked through the forums a bit, and found some similar posts, but the closest one didn't have a resolution other than to get rid of the truck,
I have a 1996 Chev Silvarado K1500 with a 5.7 liter Vortec engine. The Engine has 196000 Miles on it with very little work done to the engine other than regular maintenance.
The Vehicle is having some issues with misfiring.
A few months ago, I would get a soft code of PO300, which is the multiple cylinder misfire occasionally, but typically more often when the weather is wet.
The fuel efficiency has been reduced to about 80% of where it was 2 years ago.
Over time, the misfires have been getting worse, but again mainly when the weather is wet, or damp. The misfires are usually only noticed when maintaining speed or gradual acceleration, but not under heavy acceleration, or when the vehicle is idling.
I soaked the engine down section by section and could not get the issue to repeat on clear days. It was taken to a mechanic, and we drove the vehicle and rarely got any live misfires, but the day was clear as well.
The Cap, rotor, wires, spark plugs have all been changed. The coil was swapped with a known good one. The Fuel Filter has also been changed, and ran some water remover through the gas tank, and several engine/injector cleaners.
Recently the engine has been constantly misfiring and backfiring on cylinder 1 (PO301 soft code is constantly showing up) The spark plug was pulled and it seems to be fairly white, and has some carbon build up on the metal base. The misfires will happen when reving the engine at idle.
The mechanic is planning on doing a compression test, and pulling the "intake off the top of the engine, to look for gas pooling in the poppits" and check the gaskets.
I don't know if the original issue (PO300), and the current issue (PO301/backfires) are the same, but any additional information or feedback would be appreciated.
Thank you
I've looked through the forums a bit, and found some similar posts, but the closest one didn't have a resolution other than to get rid of the truck,
I have a 1996 Chev Silvarado K1500 with a 5.7 liter Vortec engine. The Engine has 196000 Miles on it with very little work done to the engine other than regular maintenance.
The Vehicle is having some issues with misfiring.
A few months ago, I would get a soft code of PO300, which is the multiple cylinder misfire occasionally, but typically more often when the weather is wet.
The fuel efficiency has been reduced to about 80% of where it was 2 years ago.
Over time, the misfires have been getting worse, but again mainly when the weather is wet, or damp. The misfires are usually only noticed when maintaining speed or gradual acceleration, but not under heavy acceleration, or when the vehicle is idling.
I soaked the engine down section by section and could not get the issue to repeat on clear days. It was taken to a mechanic, and we drove the vehicle and rarely got any live misfires, but the day was clear as well.
The Cap, rotor, wires, spark plugs have all been changed. The coil was swapped with a known good one. The Fuel Filter has also been changed, and ran some water remover through the gas tank, and several engine/injector cleaners.
Recently the engine has been constantly misfiring and backfiring on cylinder 1 (PO301 soft code is constantly showing up) The spark plug was pulled and it seems to be fairly white, and has some carbon build up on the metal base. The misfires will happen when reving the engine at idle.
The mechanic is planning on doing a compression test, and pulling the "intake off the top of the engine, to look for gas pooling in the poppits" and check the gaskets.
I don't know if the original issue (PO300), and the current issue (PO301/backfires) are the same, but any additional information or feedback would be appreciated.
Thank you