Car won't idle


Asked by Jun 11, 2016 at 12:00 AM about the 1975 Ford Ranchero

Question type: Maintenance & Repair

My car starts right up and runs good when
I give it gas but when I let off the gas to let
it idle it dies. Replaced the fuel filter but
didn't help. It's a 1975 Ford ranchero with
a 351m. Any ideas?

12 Answers


yes, the heat riser, spring and choke mechanism are not adjusted to and relase....also this choke has two positions as I recall..the kick-down is kicking down prematurely~

Best Answer Mark helpful

There were two systems in play back then, one was just a dash pot that the throttle contacted that slowly let the throttle close to the idle point, the other was called an anti diesel solenoid, it would kick the throttle out a bit while the engine was running and would drop it out when the key was turned off, so check and see what one you have, one is electronic the other one is mechanical, so there won't be anything attached too it.

1 people found this helpful.

If the idle mixture screws have not ben adjusted since new, this would help for a smooth idle & easier start-up when the engine is warm. Check out what tennisshoes says, this definitely can be the problem, just make sure the carburetor is all set up correctly and working properly. Should also check for vacuum leaks.


But it ran fine before and just started doing this?

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I think it may be the choke but idk

1 people found this helpful.

the heat riser is often overlooked...some have a metal shield up from the exhaust manifold they rust and people tear them off...also some models feature a thermal inlet shutoff, to stop cold air from getting in and screwing up a cold startup~ on the end of the air filter housing...sometimes..if equipped~ depending on the Coldness of the cold climate...Alaska is going to need that Alabama may not~


I have figured out its the choke. It stopped working. It's electric Choke and isn't closing. Tried adjusting it but still ain't working. It's getting power. Any ideas now?


how did you figure it was the choke, Cody, squirts of starting spray...or manually close it and it'll keep running? or pull it open for a leaner condition...really need to know if this is really the problem...often a high mileage vehicle jumps a tooth or the tensioner stops tensioning~ would be nice to know if the crank and cams lined up at TDC...that would tell you if you need new timing gear~


You will have to remove the choke cap to see if the linkage is still working, and you might want to ohm the choke cap itself just to make sure it isn't open.


bob i know its the choke because when i turn the key it isnt closing like it was before. when i warm up the car it idles. the choke should close when its cold and gradually open as it warms up.

1 people found this helpful.

okay Cody, there are a lot of parts and pieces here...take a look at what you've got that needs replacin'~ q=1975+Ford+Ranchero+choke+mechanism&biw=1280&bih=64 3&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjp19- j2abNAhUC4iYKHXzVAsQQsAQIKQ&dpr=1


do a google search on ford ranchero choke...and images and see the parts...what needs to be replaced...won't work this way..but you can easily look at the parts to see which you can replace~ here is a forum on vacuum lines vacuum-birdnest-need-a-little-expertise-please-lots-of-pics.html

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