Hi All,

I have 2000 acura tl with 201000 miles. Recently i had CEL on due to misfire. I changed the spark plugs and CEL went off. It came on again after two months with misfire codes.I cleaned EGR ports but CEL was still on with misfire and EVAP leak codes. I thought it were plugs again. Before changing the spark plugs I seafoamed and then did oil change. I then changed the plugs and used NGK iridium IX. Now the car jerks a lot in idle and also in gear. I have noticed that it doesn't jerk at cold start and starts jerking after warm up. RPM at idle and in gear are stable and good.


Can anyone help with that please?

 

check the CEL and check the coils for that specific cylinder. also IACV

 

I checked all the coils and spark plugs. They are good.

 

try resetting the ECU and having it relearn by disconnecting the battery for several minutes and then letting it idle until the cooling fans cycle a few times.
its in the service manual how to do this properly

 

check the codes, clear the light, swap the coil to a different position and see if the misfire follows it.

 

Thanks for the suggestion. After getting CEL codes and locating the two cylinders causing misfire I had to replace the coils though they seemed good when checked with ohm meter. Anyway the problem of "car jerking after warm up" is solved now. After this, I reset the ECU and disconnected the battery for several minutes. The CEL hasn't come on since reset. I have driven more than 100 miles after that.
However, I noticed another strange thing. I hear knocking sound when the car is running between 45-55 mph. No sound if I drive above 55 mph or below 45 mph. The sound is not that loud but you can hear it if you pay little attention.

Any thoughts?