The_Wraith

MY car had had a choppy idle on and off constantly bouncing I have checked for leaks and there is none. I can barrel down the express way and come to a red light after exit and the car will idle just fine , VAC gauge reads 20 , after a few stop and goes the car starts to idle choppy between 500-600rpm VAC gauge drops to 12-15. In park at idle it seems to be constantly trying to find a sweet spot. Again bouncing between 900-1000 at idle. Cold morning start up it idles at roughly 1500 right away. I can tap the gas real fast and the idle comes down to normal.

Now the other day I pulled the air cleaner off (car was warm after driving for about 20mins) and I flicked the choke plate up and down about 3 times. I got in the car idle calmed down , went for a city drive stop light to stop light car idled well and vac pressure gauge read 19-20psi I did this 3 different days with the same results. Then boom after the car is shutoff for a few hours or overnight it goes back to the choppy idle routine.

any ideas?

duckmanquacker

sounds like the electric choke is acting up and pulling itself in and out of engagement. yours probably still got the factory rivets for the holddowns, so youll need to drill them out to get a good look at the inner spring. these springs being made of bimetal on occasion wear out or break. had 2 diferent choke units on my 75 c-10 come apart and give a fluctuating idle.

naf

iTrader: (7)

When it acts up make sure the choke is wide open (blades straight up) to rule out the choke. Spray the choke linkage down real good with some carb cleaner if it's gunked up.

Have you checked for trouble codes?

The_Wraith

I have a non-cc canadian carb