not running right....

[McWulf41]

Here's the problem folks. Has an erratic misfire. At idle....revs up...revs down...revs up....revs down. Stomp on it from stand still....will throw you back in the seat. Get up to about 30 mph...falls on its face.

What I have.
345 with electronic prestolite.
Holley 670 street avenger carb.

What I've done.
New plugs,wires,coil,cap and rotor.

Help!!!!!

 

[Scoutboy74]

More information is needed. This could be either fuel or ignition related. Does the engine surge and act like it is running out of fuel at that speed? Does it recover and wind out strong when you stomp the throttle and engage the secondaries? If so, I'd suspect the primary jets are too small which would create a lean fuel ratio at cruise. That's the fuel aspect.

The ignition aspect begins with your spark timing. Do you have a timing light? Where is your base timing at idle set right now? It should be roughly 10 degrees btdc. Does your timing hold steady at idle? Is your mechanical advance working properly? If you have a dialback timing light, are you able to see roughly 34 degrees of total timing advance at wide open throttle?

Lets start with these items and work from there.