Changed the spark plugs on my 2000 xj today. Put the spark plug cover back on and started the car with no problems. Seemed to run better although it was vibrating heavily. As soon as I got a mile down the road it began to stumble when I passed about 50 mph and the check engine light come on (The car was also vibrating alot). On second check it looks the boots on the spark plug cover aren't seating right and I have no idea how to fix this or make them seat right. Does anybody have any suggestions??

Thanks,
Austin

 

redo it. tighten the plugs and just put the rail back on carefully so that they line up. i think thats what your talking about.

also, try checking the gap on your new plugs.