Engine Performance problem
2001 Jaguar S-Type 6 cyl Two Wheel Drive Automatic 90000 miles
My RMP fluctuate and the engine drags. The engine does not pick on time, also when the speed get to 100 speedometer its start jarking. A scanner was used but indicate cylinder 1 missfiring and i've changed the plugs and service the norzzle but all to no avail.