re fast idle on ford ranger ljbartel naomi b b ingr com les bartel writes it did it again this morning my ford ranger was idling at rpm ok so i exaggerated a little but it was idling very fast it has a liter carburated engine in it and no blipping of the throttle would cause the idle to drop back to normal i don t think the linkage is stuck what can i do to fix this problem this has been a problem from time to time but has straightened itself out until now i don t have a tach but by gauging by the sound of the engine it is idling about twice as fast as it should be this is down from what it was idling at when i pulled up at a stop light sometimes a bad choke pull off diaphram will cause a car to fast idle the pull off which is vacuum actuated provides a necessary pull in non cold weather conditions to get the idle off the the fast idle cam locate the fast idle cam on your vehicle and see if you can rotate it to produce a normal idle if so locate the diaphram and test it if you can t apply suction via a good piece of rubber vacuum hose with your mouth that will cause the diaphram to retract then it s bad and should be replaced bernie lofaso applied research labs
