77 Stinger

Do any of you great mechanics out there know how I can lower the rpms when the engine is idling in park, without lowering the rpms when I put it in gear? I have a 77 L82 and it idles at 1400 in park, and when I put it in gear it drops to 750. I have tried using the idle adjustment screw, but that lowers the rpm in both park and in gear, and I do not want to go lower than 750 in gear. :confused: :crazy:

Paul Borowski

Stinger, first check your return spring and throttle cable. What I think it is truely is the "fast idle" cam on the passenger side of your carb. If your choke "sets" this cam, and it's "gummy", it won't drop down your idle. Spray it with carb cleaner or WD-40. There is a small screw on this too(top of screw towards radiator)that could be hung up too. If you hold your throttle open with the engine OFF, this little fast idle pendulum cam should move freely-if it does'nt, this is probably your problem. :yesnod:

Eric 96

I thought it was supposed to be 750rpms idle in park???
I have mine set at 750rpms when in park, and it drops to 500rpms in drive. If I bump it up any higher, I get a little run on when I turn the engine off.

yellow 72

I would look for a dissconnected or broken vacuum line :smash:

77 Stinger

By adjusting the fast idle cam down, will it affect the rpm in gear? :confused:

77 Stinger

Any ideas on which vacuum line would cause this? :confused:

jvm

I had almost the same thing on a 4 speed. Turned out the centrifical weights were sticking on the rotor cap. High rpm wouldn't shut down.

Pop the distributor and rotor cap, check for rust marks on the underside of the rotor cap where the weights might be rubbing

Neo Fender

Second this. Don't just check for leaks at the carburetor. Follow every line to its destination to make sure the vacuum line is intact.

77 Stinger

Is there a way to isolate just the vacuum that would address just the carb. Keep in mind that all the emission junk has been removed from the car. I basically looks like a 350 from the early days when they were not all cluttered up.:confused: :smash:

jvm

Take a can of carb cleaner or WD-40 and spray it around the carb with the engine running. if there is a vacume leak where you put the WD the engine will speed up . Jim

yellow 72

Check the large and most obvious lines first, brake booster, pcv, and any line connected to the carb first. not only for them to be dissconnected but for cracks, particularly the undersides.