Help needed

My 72 with a 455 and QJ has developed a stumble under hammering the peddle, the only time it does this is when I push it. It is like the engine is shutting down, then it picks back up. The first time it did it was on a highway accelerating ramp. I thought it was fuel pump at first, then the other day while on the highway going 65 I pushed it to go a little more and it stumbled like a ticking clock. On/off/on/off ect. If I let off the pedal and accelerated slowly it would not do it, only if I hammer it.

Can anyone tell from that description what is wrong?

Thanks,
Jerry

 

I suspect your accelerator pump is bad. Probably need a new gasket.

 

Do I need a new pump, gasket or both?
So could this also be a reason for poor start up after sitting a couple days? And it takes a long time to warm up from high idle from start?

 

Yes, the bad accelerator pump can also make it harder to start.

Make sure you get a quality accelerator pump with garter spring like cliffshighperformance.com sells. Don't just get a "blue" pump, and for sure don't use a black pump. Those won't last long with today's fuels.

You have to pull the top off the carb to replace the accelerator pump, so you should also get a new gasket.

 

Check them thar wires from the moduel under the dist. cap sometimes they rub and start to short when the vacume is lost all of a sudden.

 

I checked with a couple guys on here and I am leaning away from the carb as the issue. I'm looking into ignition and here is what I'm trying next...
Well, the resistor wire had a questionable connection/crimp where it was spliced at the point it goes to the coil and down to the starter solenoid. Now if it wasn't raining I could go and test it out. I also looked into the distributor/XR-i ignition module. This wiring looked good but I did turn up the rev limiter to about 6500 from 6000.
I gotta run out the old fuel, get new plugs and test out my plug wires....

It's not easy bein green...

Thanks!

 

Thanks Larry! I will put these items on the list...