Ol' Bitty threw me for a loop today and wondering if anyone knows whats up. First time I drove my 75 scs with 460 and c6 allstock a long distance, and performed great, except for the last half hour. I thought at first the throttle linkage was sticking, id let off the pedal and shed keep going. Then in town it really sounded like it sped up after i let off, a quick snap of the throttle and it would idle again. But then I was going down hill towards a red light and rested my foot next to the pedal, and it happened; the pedal moved down and she went up to about 1400 rpm, no time to snap throttle so popped it into neutral and hit the brake, back to idle.

any ideas, this thing does t have a cruise control, I think, so what could actually move the throttle on me?

 

It would be a really good first step in troubleshooting to check for the throttle binding or hanging up on something.

Let us know what you find.

 

How are your cab mounts , motor and tranny mounts ?

 

I seem to recall that cruise control on an old carbureted engine adds more mechanical linkage to the mix......either a parallel cable running right alongside the regular throttle linkage, or above or below the normal linkage from the gas pedal. because of the extra stuff, you may also have a heavier spring or a couple springs designed to bring the throttle back down to idle when you let off on the gas. things could have become damaged, or are getting hung up on the bottom of the air cleaner housing. i would examine all throttle linkage, see if anything looks to be binding, or needs lubrication

 

Nothing seems to be binding, lubed all the moving parts anyway, as for mounts, it is an old work truck but is fairly solid, and this was happening on straight smooth roads with very little torque differences, and the pedal physically moved at least an inch while going slow with no change in speed or bumps to move worn out mounts etc. So I doubt it could be that

whats the thing next to the master cylinder connected to the linkage? Hot idle somethin or other, any way it could be activating?

 

Next to the master cylinder? and connected with physical linkage, not just vacuum hoses and wires? that sounds like something related to Cruise control, maybe an aftermarket unit? anything related to tranny kickdown should run straight back over the back of the engine, and down to the tranny, not next to the MC

 

Ya, connected to a servo with a small link chain. Its a pushrod attached to the throttle linkage via the small chain, ford stamped and says hot idle or high idle and cant make out the rest. Its round and near the master cyl...

 

that does sound like an aftermarket C/C unit. post pics. if it is a C/C, then disconnect it from throttle linkage