Sticky Throttle

[Cool Mr Steve]

My car idles horribly when it warms up (when it's cold to, but from unrelated issues). After using the throttle, the car idles anywhere from 1400 rpm to 2000 rpm. If I tap the pedal it will die back down to a reasonable rpm most of the time. If I stop the car and go under the hood in one of it's crappy idle moments, I can push the throttle back to where it should be and it will idle correctly. The problem definitely seems to be that the throttle is sticking slightly open, but I have had the throttle body off and cleaned thoroughly around the throttle plate and in the bore (not sure if I'm using the correct term, but the main passage where the butterfly plate sits) and the plate still doesn't want to be happy. The throttle cable doesn't seem to be the cause, as it still has some slight slack when the problem is happening. It almost seems as though the springs not being wound tight enough may be the culprit, but I wound it two complete turns... Is this enough, or should I go for 3? Any ideas?

 

[VelocitàPaola]

The throttle cable doesn't seem to be the cause, as it still has some slight slack when the problem is happening. It almost seems as though the springs not being wound tight enough may be the culprit, but I wound it two complete turns... Is this enough, or should I go for 3? Any ideas?

If you're able to tap the pedal and have the RPMs return to normal, its most likely an issue of insufficient lubrication somewhere along the line. Raising the tension of the springs will help, but that still means there is friction somewhere causing premature deterioration. Check every little piece on the throttle body, but be more concerned with the outer pieces rather than the butteryfly plate. If needed, lightly lubricate it with an aerosol lube like silicone. Just for good measure, if possible, lubricate the cable too.

My first instinct when reading this was that the shaft connecting the butterfly plate to the outer pulley and cable was bound somehow and needed better lubrication.

 

[christiane]

I had this same problem with my car as well. I believe it was related to the cruise control unit. My 'fix' for the problem was to remove the CC unit and go with a non CC throttle cable. No problems since then. If deleting the CC is not an option for you spray some lubricant into every cable (inside the sheeth) as well as the CC assembly.