I have and '86 F-150 with a 5.0L 302. At about 1000 rpms it shakes real bad. If i mash the pedal or let off, it smooths out. It also shakes a little while idling. I'm thinking IAC Valve maybe? any thoughts?
thanks

 

check your motor mounts, see if the motor is pulling at certain rpms.

 

Motor mounts are fine. I replaced the IAC valve and nothing. I was told EGR valve now but am hesitant to spent another 80 bucks. I appreciate the help.