I have a beloved 2008 Honda Fit with 130K miles on it.
I replaced the spark plugs myself last year with OEM plugs. They came pre-gapped and I was told not to gap them but I measured the gap and it was larger than it was supposed to be. However, I followed instructions and did not gap them.
A few months ago when it was blazing hot outside it began shaking/shivering when I was stopped at stop signs or red lights and the car was in drive. It seems especially bad if the air conditioner is on. If I put it in neutral it stops and/or is severely reduced.
I took it to a shop and they said it was not the air conditioner. They said it was the spark plug boots. They replaced the boots. I took my car home and the next day the battery was dead. I took the car into Autozone and they replaced my battery since it was only 1 year old. They said the connection to the terminal was not a good fit and this is why the battery died. The new battery they put in also did not connect well but they added some pieces to make the connection tighter.
After that my car seemed to work fine… for about a week. Then the shaking started again. I took my car back into the shop and they said it was misfiring on the 3rd cylinder so they replaced the 3rd spark plug coil. I took the car home and it was good for about 2 weeks. Then the shaking started again.
I took my car back into the shop and they said it was misfiring on the 2nd cylinder so they replaced all the spark plug coils. I took the car home and it was fine for about two weeks. I noticed it ran a little louder than before (it sounded like it was purring) but no shaking. After about 2 weeks the car started shaking again.
I have talked to several people who have different ideas about what it could be but I wanted to hear what you guys think before I take it into another shop or try to troubleshoot the problem myself.
Many many thanks