I replaced the valve cover gasket last night and let the sealant set over night, came out to the car and start up seems fine except a hard shake and obvious tone from exhaust like it is cammed or something. Did i mess up the spark plugs and reverse a couple cylinders or what? please help, i have a lot to do today, dont feel safe driving car this way, and this is a huge problem...

 

k, i tried the spark plug wiring both ways with no results, also i have a Service Engine Soon light. Wish i has a code reader but i do not, and dont wish to drive car to find out what this is. Only other thought is i may have bumped loose a injector? Does this seem possible with my problem? thanks again

 

hot damn im good, guess it pays off to learn how this stuff works on your own. Was the injector, they were a little loose when i installed the stock ones back onto the previous injector harnesses. When re setting the valve cover in the dark i popped the back injector harness right off the injector. The noisy thumping i was getting was a cylinder not firing properly.

Hope this helps someone that runs into this down the road.