I Have a couple of things going on with the truck, and I was hoping I could get some good feedback from you guys. 93 F-150 302 4X4, 5spd, 4:56's, Detroit in rear, and 6 inch lift with 35's.
1. This one involves clutch/tranny. When I shift from 2nd to 3rd , and some times to 4th there is a slight grind. It feels like the clutch is not quite disengaging. The slave, and master are about 12 months old. the clutch is center force 2. I have tried the test of putting the truck in 5th and releasing the clutch to see if it engages and motors rpm drops. Well that works it will try and move with little effort.

2. When I'm at highway spds and let off the gas to coast i get a small bucking type motion and some vibration. The T/C shift lever with also vibrate, but if i give it a little gas then it stops vibrating? I know that with the locker in the rear can cause some bucking. but the vibration is quite annoying.

3. I loaded my truck with my camping, and fly fishing gear for the annual Green river trip. There wasn't a lot of weight in there, but the truck had no power i was having to down shift all the time to maintain freeway spds on slight uphill grades. I know the 302 isn't a work horse but i should have been able to cruise all day long with no problems with my gearing i would think. My fishing buddy even went so far as to say "We should have brought the Chevy" and thats what hurt my feelings. LOL. I am considering installing headers and new high flow cat, but is this really going to help me. BTW its only been about 8 months sense i did a total tune up.

 

Read this post and his answer after he replaced his cat(s)........sounds like it could be part of your problem. Headers and cat will definitely help.

https://www.ford-trucks.com/forums/613873-no-power.html

Have you checked the free play in the clutch pedal....might just need a little adjusting because it seems to be working ok other than the little bit of grinding on a few shifts.

Vibration could be u-joints.

Good Luck