Misfire (chugging) under light acceleration

Good morning,

I would start with the coils. An ohm test is not accurate to see if one is breaking down under a load. The only way to accurately test the coils is with scope to watch the spikes when under a load.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

You have already done the plugs and boots which are the most common.

start there and check back with us for the results. Let us know if you have any other questions.

Roy

Hi. Just to jump. You mentioned there is no check engine light on. Have you tried to scan for codes. Here is a link on how to do it with a scanner.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If there are start/cold misfire codes then you should check for leaking fuel injectors or leaking head gasket. That would cause a misfire on first start up in the morning.

If the misfires are random and you have an advance scan tool go to mode6 and look up test ID 56. The cylinders will be 01 for cylinder 1 02 for cylinder 2 etc. Look through all of them. The one showing a high count will be the one causing the problem. Most likely the coil but you could have a bad injector as well. The high count cylinder swap the coil to another cylinder and reset the codes even if there is none. Road test to get it to misfire and go back to mode6. If the high count follows the coil you moved that is the bad coil. If no change do the same with the injector. If it follows bad injector. If no change then you have a mechanical fault like sticky valves.

You are welcome.

Always glad to help.

Roy