I am working on a 97 f-150 with a 4.6 w/automatic trany. It has 170,000 miles on it. It has a vibration at idle when it is in gear, and a vibration in park at 1800 RPM. The truck runs fine going down the road. Any suggestions on what the problem might be. Thanks

 

Check for a vacuum leak.
My 98 has a vibe at about the same rpm in park. It does not vibrate at that rpm while the truck is moving. I don't rev it to 1800 in park anymore.

 

Thanks I will look for that.

 

1993F150,

Did you ever resolve your problem?

Sean