1994 Buick Park Ave

I have a 94 Park Ave and when driving the motor shakes bad and when you try to get it gas the motor shakes and doesn't pick up speed fast I've changed the fuel filter, plugs, wires, crack & cam sensor added lucas fuel cleaner and dry gas and sometimes it shakes, and sometimes it take awhile to shake. Very slow pick up speed. Please help.

Have you checked it for trouble codes? Also, when you say the motor shakes, it sounds to me like bad motor mounts?

Sounds like a coil pack issue. Are you getting spark on all coils? You did get non-Bosch plugs, right???

I don't think bad motor mounts would affect slow acceleration so I would suggest that you also check for a vacuum leak. Another possibility would be a clogged catalytic converter. Put your hand under your tailpip and see how much exhaust is coming out...if you cant feel much air or just a puff once in a while then that would be your problem (probably).

In addition to the above suggestions, you could be near the end of the service life of your timing set, or have the infamous cam gear interrupter, (magnet) issue. Loss of power in addition to "motor shaking" is a key indication of timing problems. How many miles are on this car?