dodgeboy49

I have a '79 f-150 extended cab with a 351 modified. I recently finished putting a new head on the passenger side of the engine b/c it dropped an exhuast valve. Anyways after I hooked everything up a new problem has occurred, occasionally when I lightly step on the accelerator something sucks it straight to the floor and I am going down the road with the pedal to the floor for 10 seconds or so, then it suddenly stops, any ideas what could be causing this?

Thumper

nope but that sure would make me want to goto the dragstrip and stop playing in heavy traffic!!!

351w

i dont really see a problem with that condition other than the fuel milage might be down a bit.
but anywho , the only thing that i have ever come across that would manually pull the throttle is the cruise control system and i have seen them somehow manage to stay on when the button was pushed to turn it off and the ignition could even be turned off or the brakes applied, all of which should have killed the cruise control.
cruise control should not function a slower speeds if i am correct and i could see it coming online when you reached say 30 mph if this is the case.
but then again not all vehicles in 79 had cruise and so ends my rambling.
so in short you better add another throttle return spring to compensate for your lead foot !

Believer45

The same thing happened on my 1967 Impala SS 327 - it was a broken motor mount on the right side. The engine would torque over, raise up and pull the linkage to the floor.

Dave / Believer45

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'95 F250 power stroke 5 spd 4x2, mfg 3/95 in Kansas City, extended cab, long bed, 3:55 rears, open air filter, 285/75x16 Cooper Discoverer ATS tires, Putco master boss running boards, aluminum cap on bed, custom rear bumper (@350 lbs additional weight), scale weight full of fuel, me in it (285#) - steer 3420 drive 3160 gvw 6580, 222,000 miles on my way to a half million.