Did you jumper the test plug when you did your timing? Timing should not be moving around that much when jumpered. With the test connector in you want 5 degrees BTDC. But if you are at 5 without the test connector in the timing is retarded much to far. Should read around 12 in normal idle operation (un-jumpered) but that can vary.

A friends truck behaved this way when the timing was way off, like ATDC. Turned out we had a bad timing light.

The vac hose off the dashpot is normally connected to a tiny air filter. It should not have actual vacuum on it.

 

Yeah I have it jumpered when I set it. I testing my timing light, it's working fine. I don't think it jumps around all that much.. 4-6 degrees

If you take a look at my latest pictures.. I'm replacing my injectors this week. If that doesn't fix the issue I'm not sure what I'll check next. :/

 

While I think replacing the injectors is necessary and will help, looking at the wiring in your photos tells me you have a lot more to fix and diagnose.

 

Wish there was someone nearby that had a clue how to do it.. because it's outside my skill set. Any idea what that bottom connector is for? I know the wire would be impossible to tell me.. but the connector seems fairly unique.

 

Hmm i wonder if your total advance is messed up? Have you looked at timing without the connector in? I have heard there are a lot of early ECUs that advanced way too far and cause the miss you speak of.

That's a tough one on the wiring. Mine has some extra A/C wires hanging out unconnected, even though my truck never had factory A/C.

 

While in my driveway the timing seems fine, under idle and when I give it some RPMs.

I put in new injectors today, going to redo the injector connectors. Still trying to figure out what the empty connector is. I think the single wire is for the A/C compressor that it not hooked up.

 

Thanks for the help everyone! I re-did the wiring today and replaced the injectors. No more miss!