About 2 weeks ago I installed a new motor mount (driver side mount, the easy one to get to) and just yesterday new spark plugs and wires. My car is still shaking a bit at a stop light but my check engine light isn't on. It did come on once before but then after 1 day it went off and never came back on. The guy at the auto parts store told me he can't check the codes if the light isn't on.

I read somewhere that I should re-loosen and re-tighten my motor mount. Is there a way to check to see if my oxygen sensor or fuel filter is bad?

*edit*

I re tightened the battery cables because sometimes during idle or start up the lights in the dash would began to dim and then return to its original brightness. I thought the battery cable was lose. So I lost my chance at getting the check engine light code

 

Don't have a clue. What car are you even talking about? And you can pull codes with a paperclip in less than 5 minutes.

 

What is your idle running at it? It mite be a bit too low ie 600 or 700 rpm it should be around 850 to 900 rpm. Adjust the throttle cable at the throttle body. Hope it helps.

 

What car is this exactly?

 

Adj timing to spec, then check idle.

 

I would also check your egr.