Hi all,

I have been batteling a bad shimmy in my 89 f150. I thought it was a bad spark, so I replaced the sparks, no luck. Next I did the fuel filter, still no luck. So maybe the cap and rotor, nope. The plug wires are brand new so I dont think its them. The truck was running fine until it sat for a week while I was away. Now when ever I step on the gas the whole truck shimmys back and forth. Any ideas. Thanks

 

If it idles fine and coasts fine when you let off the gas it could be a bad u-joint.

 

Re-check your firing order ,you may have swapped a couple of wires.