Heavy miss / stumble at 1500+ RPM.

[Edelbrock]

All of the sudden the rig can't accelerate. Heavy heavy miss and stumble about 1200 to 1500 RPM. Lurching and popping if I floor it or even try to accelerate normally. Have to baby it. Also, when the engine cuts out and stumbles, the tach needle drops, like the power supply is cutting out. Needle drops way faster than RPM and then bounces back up and registers properly then drops again. This is not fuel related. It's a short in the distributor or something. Should I just run a jumper from the battery to the distributor and unplug the tach, just to get home? Just baby it home as is?

 

[Matt69olds]

Does it have HEI? If so, temporarily disconnect the vacuum advance. If it improves or is solved, carefully inspect the tiny wires for the pickup coil in the distributor. If the wires are broken or damaged, more than likely you found the issue. Replace the pickup coil.

The problem is caused by the vacuum advance rotating the pickup coil. After those wires flex a few thousand times, the wires break and cause the ignition to fail.

 

[Edelbrock]

Update: problem solved.

Does it have HEI? If so, temporarily disconnect the vacuum advance. If it improves or is solved, carefully inspect the tiny wires for the pickup coil in the distributor. If the wires are broken or damaged, more than likely you found the issue. Replace the pickup coil.

The problem is caused by the vacuum advance rotating the pickup coil. After those wires flex a few thousand times, the wires break and cause the ignition to fail.

Thanks. I was thinking it might be vacuum related. But I got it sorted out.

Update: moved the distributor / tach wires around (and choke, which is wired into the dist.+ Wire). That solves it enough to get me home. Ran fine. But there is definitely a short on one of those wires that I will need to investigate. I think the short was cutting power to the dist.

 

[Ricko1966]

Update: problem solved.

Thanks. I was thinking it might be vacuum related. But I got it sorted out.

Update: moved the distributor / tach wires around (and choke, which is wired into the dist.+ Wire). That solves it enough to get me home. Ran fine. But there is definitely a short on one of those wires that I will need to investigate. I think the short was cutting power to the dist.

Your not supposed to run the choke off of the ignition lead.