hey I've got a 88 royale oldsmobile and I think it's got a misfire but im not entirely sure. The car would shake at the lowest speed but I changed the spark plugs and the wires and air filter. After doing this the car now only shakes when going above 50mph and I was wondering if anyone might have some input to what might be able to fix this?

 

I would have the tires balanced and see if that cures it. If that doesn't then I would have the half shafts checked as well as the front bearings.

If you have eliminated the ignition then is has to be something that is spinning in the running gear.