About two months ago I was getting a cylinder 5 misfire so I replaced the spark plug and problem solved. I started to get another misfire about two weeks ago. Decided to replace all spark plugs and coils. When I got to my 4th cylinder it was covered in oil (I'm assuming the valve cover needs to be replaced). So I finish the install of coils and spark plugs. Misfire is gone however I notice loss of acceleration and I feel a lag with the power also ( its like I don't get the power until 4k rpm and then my car is finally like okay go and then the speedometer takes a second to catch up). I do not know much about cars so I'm reaching out to see if anybody can help me out with suggestions. No check engine light and its a 2004 coupe with 182k on it.

 

Is it a 6MT? Sounds like a slipping clutch if the tach and speedo don't match and the speedometer is "playing catch-up".

 

If it's not a slipping clutch then check to make sure you plugged all the coil packs into the correct harness. It's possible to mix them up but the engine typically runs really rough.

You should do an ECM reset anytime you change plugs.

 

Yes, 6MT. I replaced the clutch about 20k ago and noticed the RPMs were a little different after but no real power loss. The clutch feels fine and I already went back over the coil packs. I didn’t reset the ECM though.

 

What plugs did you put in? I only run NGK in japanese cars.

 

ngk

 

What valve cover did you go with, I have oil leaking into one of my spark plug wells. I’m going to replace my valve covers and gaskets (obviously), but not sure which one to go with. Don’t want to break the bank either.