Hello. I'm new to this forum, so please bear with me. I have a 1970 Dodge Challenger with a 340. She's been sitting for a couple of years, but started right up, and ran no problem. I recently changed the driver's side exhaust manifold gasket and the gasket going from the manifold to the tailpipe. Now she starts, but will only idle if I keep my foot on the gas. I changed the spark plug wires, ignition coil, ballast resistor. I will soon change the cap and rotor as soon as I get a rotor. I can't for the life of me figure out what the heck is wrong!!!! It's frustrating the heck out of me. Please, anyone, HELP!!!!

 

If it has been sitting ? I would check and see if the carb is flooding/ floats sticking

 

Already tore it apart and put it back together. After that it was running great. The needles were stuck, but that was fixed.

 

Skip -

Sorry to ask this, but where is the curb idle screw set???

You should be able to turn it far enough it for the engine to stay on, without idling at 2,000. If that's not the case, I'd check the flow through the idle circuit and possible vacuum leaks.

Really doubt it's electrical, however how's your alternator doing? Loose any diodes lately - no, I'm not kidding.

Archer

 

You could have got more crap from the fuel system, hanging the float again

 

You can easily see if the carb is flooding due to stuck floats/ needle/ seats, just look down the carb throat!!

It is also likely that the carb, and indeed the rest of the fuel system is gummed up. The idle circuits inthe carb may be plugged. This can happen with the slightest amount of dirt. Sometimes you can simply pull ONLY the idle screws and squirt a forceful stream of pressurized carb cleaner in them and dislodge the obstruction.

Sometimes pulling the screw out, starting the car and controlling the throttle with one hand, put your finger over the screw hole, which causes a high vacuum in the idle circuit will pull the dirt out.

 

Thanks to everyone that responded. I'm going to check the carb this Saturday.

 

Siphon some gas out of your tank and see how it looks. I haven't had one yet that didn't need a new gas tank. Might do that before you start running the gas through your carb again. all the microscopic pieces of rust and turpentine that do get through your filter will do terrible things to the carb. Also might check to make sure you don't have any vacuum leaks anywhere. Another possibility but probably doubtful is timing. Might try turning the distributor a few degrees either way to see if that fixes it. My 76 celica did this exact thing once. Wouldn't stay running on its own. I had to keep pumping the gas to keep it running. I advanced the timing just a hair and it completely fixed it.

 

you may have a tank full of rust.