Hi folks, I have an 01 Concorde lxi. Check engine light is on, codes say #1 cylinder misfire. I changed all spark plugs and the #1 coil. Made no difference. Dealer says it could be carbon buildup on the valves. compression test was good. all feul injector are being triggered by ecu. It runs terrible. Anyonehad this problem before?
Thanks alot

 

not sure what engine you have.have you tried spraying carb cleaner around the intake area? might be cracked intake gasket.moe