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Discussion Starter #1
I have some issues with my car;

1. Whenever I start moving from a stop, about half the time when I hit the gas, there is either no response and the car dies, or if it's lucky, it'll fire up after a second or two. Also when it is sitting and idling, sometimes it'll die, but the idle is usually rough.

2. Just recently, it started screwing up at 40 - 50 mph, it'll jerk back and forth a bit, then just slow down until it gets to 30. Here, it is fine back up until that speed where it stops accelerating. Half the time here it dies at 30.

Any thoughts?
 

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Put a t in the fuel line after the fuel pump and install a temp fuel psi guage and set it inside the car or tape it to the windshield so you can see it and see what the psi is doing thats a good first start
 

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hesitating 1970 chev

I agree it is likely a fuel issue. The big three would be fuel filter, fuel pump or fuel line issue. IN the fuel line issue it could be a collapsing soft neoprene line or if your car has the fuel recovery system (pollution device) it can plug causing significant hesitations.

Capricious69
 

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Problem number 2 is most likely the fuel pump.

Problem number 1 may be the accelerator pump in the carb not pumping extra gas when you hit the foot feed. With the car shut off and the aircleaner removed open the choke an move the throttle as though you were wanting it to go faster (or have some one pump the pedal for you) and see (carefully maybe with safty glasses on) if gas squirts up towards the choke if it does good if not you need to replace the accelerator pump in the carb.
 

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I'll go with 77Impala on the accelerator pump for #2 , I would first change the fuel filter for #1, should be right at the carb, unscrew the fuel line from the carb it should pop out because of the little spring behind it, IIRC.
 

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I've had experience with the ignition modules being a problem too, but I don't know about 70, that might be a different story. If you have one it'll be under the distributor cap, and also the coil in the distributors cause a similar problem. So there's a chance you may need a distributor.
 

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I've had experience with the ignition modules being a problem too, but I don't know about 70, that might be a different story. If you have one it'll be under the distributor cap, and also the coil in the distributors cause a similar problem. So there's a chance you may need a distributor.
GM started using the HEI system in 1975, but some people have changed the pre-75's to HEI's, so that may be the problem. Would not hurt to check and see if the distributor has points-condensor or HEI electronic module.
 

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Discussion Starter #8
Aww man, thanks guys for helping me out! Much appreciated. Well, I took apart the carb iot clean and rebuild it and some sucker stole it, so I bought a holley and a new intake for it, now the car works almost perfectly, just need to fix a few seals and figure out how to attach the transmission lever to the carb.
 
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