Weird Vibration - Help
 

Ok....this might be a little hard to describe but here it goes.......

I have a 2001 V6 - Automatic and when driving at lower speeds (less than 40mph) I get a jerking feeling like the car wants to shut off - very slight jerking. When i give it gas it stops. I have noticed it more when I run 89 octane and less when running 93 octane fuel. My first thought is maybe dirty or clogged fuel injectors. Any other ideas?

Does it happen when cruising, at full throttle, or at slight throttle?

Sounds like it could be a missfire problem.

When Cruising
I does not do it all the time.

it might be your car telling u it wants to be manual and not automatic

Sounds like a "going bad" coil pack which is giving you a missfire. Does it feel like a hesitation? Could also be a bad knock or ping, but sounds more like a miss. The problem will get worse if it is a coil pack.

Could it be a bad spark plug not a coil pack?

plugs were replaced approx. 4-6 mos. ago. they were replaced with motorcraft plugs. its almost like its skipping when its at about 2-3000 rpms. not necessarily a certain speed. the check engine light has been on since i bought the car and the code said it was the EGR valve so i had it replaced. the light went off and came back on so im going to have it checked and see what its saying now.