# Throttle hesitation at certain RPMs



## Pss02258 (Sep 19, 2020)

Hey guys, 

I’ve owned my 1970 GTO 4 speed for a few months now; and I’ve developed a lag in acceleration at certain rpms. When I’m going hard on the accelerator , it’s accelerates Fine. But when I push on the accelerator at, say 35 mph in 3rd gear and low Rpms; it stumbles and lurches. I’ve been told it could be the accelerator pump , which I had looked at and seems ok. Or maybe advanced timing? Any help would be appreciated.


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## Lemans guy (Oct 14, 2014)

Yes those are both possibilities,...your distributor curve could be off. The weights and springs could be sticking. Pop off your dist cap and rotor and have a look see if your springs and weights look ok! Sometimes a weight can run up on the dist cam or a spring get too stretched or disconnected....

Accelerator pump could be weak or the pump cam arm needs adjustment, so the cam works instantly, any gap and it will lag....

Both good places to start......and I always use Redline S1 complete fuel system cleaner, goes in your gas tank. It is real, not snake oil, it has Techron the chemical developed by Chevron chemists to clean your system. It even has more Techron in it that a Bottle of Techron!...


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