ok, i have a 1990 f-150. it's a 2wd w/ 4.9l I-6. auto trans. and 161 on the odometer. i've been having this problem for awhile now, and tried several things to remedy it with no avail. here's the problem. when i'm on the freeway or going up a hill, and try to either maintain throttle, or roll on a bit on the gas, the truck starts vibrating. it's a drivetrain vibration, and can be felt throughout the truck. immediately i changed plugs, wires, distributor, and rotor. the problem prevailed. next logical thing was fuel filter. while the truck runs a bit better normally, it still vibrates the same. the other thing is, if i am running a constant speed like 45-50, and slow to a halt, it idles rough. i am at a loss right now. the truck is my winter beater, and i dont want to plug alot of money into it. i've run it on 87 octane since i bought it, and so did the previous owner. the only thing i can think of right now, is that the injectors are shot. i ran some cleaner through the system, and the problem is still there.
any help would be greatly appreciated
thanks in advance
-matt

 

Maybe a problem with the torque converter not unlocking/relocking improperly?

 

feels like a fuel delivery/combustion problem, but torque converter could be. what could i do to remedy this problem? is there anything i can do w/o replacing the torque converter? i was also wandering if it could have to do with EGR/02 sensor, or the fact that i run 87 octane in it. i was thinking of disconnecting the computer to get a fresh start, and running 89 octane.

this is my winter beater and i'm trying not to sink to much $$ into it.

thanks
-matt

 

have you checked your fuel filter and fuel pressure yet?? What about the universal joints. Check the simple first.

 

i beleive that the vibration i am feeling, is detonation, or pinging.

i think i need to clean my EGR, and run some premium through it. it may be a vacuum leak as well.

i know these engines were meant to be run on 87, will running premium through it hurt it?
-matt