Couple questions to start. Is there any noise when you are doing this? Noise like marbles in a tin can? This is detonation and it is unburned fuel igniting in the exhaust.
Next, did you do all of this to try and fix this issue or is this happening after the parts were replaced?
This could be as a result of incorrect timing or bent valves.
So if this was done to try and correct this we need to next do a compression test and a vacuum check with a gauge.
Below are the readings from a vacuum gauge that will help with this issue. Let's start with this and if this all checks out then we can move on to a possible fuel issue.
If you can get a video or what the vacuum gauge is doing while idling and then running rough that will help us figure out what is wrong.
Thursday, April 29th, 2021 AT 10:07 AM