We have a 1999 F150 extended cab 5 spd with +150k miles. We first noticed the hard idle several months ago along with a hard shutter when starting off in 1st or going in reverse. The shutter does not happen in any other gear. The mechanic has replaced the clutch twice (under warranty) and turned the fly wheel once - this last time. We have also had the idler arm replaced, twice (under warranty). All the tests show nothing wrong. The mechanic we see is good, he takes care of our '93 escort (+330 k) so I trust him. We made a huge mistake of going to another for convenience and they dropped the clutch while attempting to fix an oil leak. They didn't say anything until we took it back for the shaking. They replace it, but the shake quickly came back and we went back to our original mech. He replaced the clutch with a much better one. The shake got better, but it's still there. After each visit, the shutter is better, only happening intermitently, but slowly gets worse. Gas mileage is OK considering the ethanol and runs good otherwise. Any suggestions to what might be the problem would be greatly appreciated. I have read a few other threads, but the suggestions that were made have already been tried. Thanks in advance for any help!

 

Only thing I can think of is motor/transmission mounts. Has your mechanic checked for vacuum leaks and checked diagnostic codes?

 

Yes he ran the diagnostic codes, but not sure about the mounts and the vacuum leaks. I would like to say he did, he's pretty thorough with his work, but won't hurt to ask. If he has, I guess we will keep on searching.

Thanx for the advice.