• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

68 Roadrunner driving itself

Hamarler

New Member
Local time
7:32 AM
Joined
Sep 13, 2021
Messages
2
Reaction score
0
Location
College Station
I have a 68 RR 383 4spd with a 9002 Holley carb. When I was driving it last time it started ‘driving itself.’ It started idling very high and it would not go below 2k rpm’s even with the clutch in. Even when braking I was fighting the car wanting to rev. Any thoughts what this might be?
 
Might be a limp return spring. Just don’t be this guy.

 
Like posted, week return spring. ( most guys run 2 )
Throttle cable could be hanging up inside the plastic sheath. ( check cable clamp on the intake for correct clamp location and make sure its not mashing the cable housing.
Check carb base gasket for correct size and that the butterflies are not catching on the gasket.
 
questions like this scare me...... at a minimum, all of these cars have been fiddled with multiples times over the years.......

you MUST UNDERSTAND AND INSPECT the entire function of the throttle assembly, from the gas pedal to the carb; or risk a serious mishap
 
Heed to the warning that your getting from your ride and don’t be like the 1,300 HP
comet owner and ignore it.
 
Last edited:
If a 4bbl carb, check that the sec blades are not binding, caught on gasket etc.
 
Don’t forget to check for a large vac leak.
 
I have a 68 RR 383 4spd with a 9002 Holley carb. When I was driving it last time it started ‘driving itself.’ It started idling very high and it would not go below 2k rpm’s even with the clutch in. Even when braking I was fighting the car wanting to rev. Any thoughts what this might be?
Throttle return spring, two springs are better than one.
 
Unhook the throttle cable from the carb. Put car in N, park brake on. Start it up. If it is still idling high, check for vacuum leak off the carb pcv port and vacuum advance ports.

If you have an choke, make sure it is stepping down as it heats up.
 
I have a 68 RR 383 4spd with a 9002 Holley carb. When I was driving it last time it started ‘driving itself.’ It started idling very high and it would not go below 2k rpm’s even with the clutch in. Even when braking I was fighting the car wanting to rev. Any thoughts what this might be?
could be choke stuck open.
 
I have a 68 RR 383 4spd with a 9002 Holley carb. When I was driving it last time it started ‘driving itself.’ It started idling very high and it would not go below 2k rpm’s even with the clutch in. Even when braking I was fighting the car wanting to rev. Any thoughts what this might be?
If you've never seen the movie "Maximum Overdrive" , now might be the time.
 
Auto Transport Service
Back
Top