Serious Miss

88 Renix, has been popping occasionally at or near 2000 RPM`s. It crapped out on me big time today (in the middle of a thunder strom), barley ran. Fuel pressure is good. Coil cable checks out OK. Kind of acted like fuel, but also like a serious timing event. It was popping pretty good through the TB.
I unplugged the vacuum line at the MAP and it shortly started running well enough to get me home (though way rich and wouldn'r idle). Plugged the MAP back up and everything ran fine? I swapped out the MAP with my spare, just in case.
I also dowsed the whole left side of the motor with water, just to see if that was it, ran just fine.
Any other ideas, of things to look at.

Remove the distributor cap and check the rotor for excessive rotational play (worn distributor drive gear). While the cap is off, turn the crank with a wrench and see how many degrees of crank rotation you need before the rotor starts to move. If it's a significant amount, this would indicate an overstretched timing chain.

I'll check out the distributor, now that you have brought it up, I remember hearing a clicking sound from the distributor area last week. Something that caught my notice, but didn't seem critical at the time (been working double shifts). A while back I also noticed the shaft has a lot of up and down play, but not really much side to side. I think one of the shaft shims is worn through and probably gone, the only thing keeping the distributor shaft down is probably the rotor contact. I`ll order a new distributor gear and see if I can't find a bronze washer or something for a shim and try to get the probable up and rotational flutter out of the distributor some.
I also noticed my mileage was getting pretty darned good for the last couple of weeks, before it crapped out on me.
It acted like the distributor was wet, but wouldn't go beyond idle, no matter how much I feathered the gas and tried to get the RPM's up some. But the distributor was dry (first thing I checked). I also thought back to make sure I used the gas pump and not the diesel pump when I tanked up this morning. The Gas station tanker pulled in just as I was leaving, I may have topped of with a tank of wet/dirty gas.
About the time you think you've seen it all, the old Renix throws something new at you.
I think I'm also going to check my Cam position sensor, just for the heck of it.
The rear main is leaking again and the CPS is probably covered in oil, the CPS is fairly new, hope the oil didn't seep into it.
Time for some serious maintenance.

I've had the MAP sensor hose get clogged up and send a bad signal that made it run bad.

On a few occasions I have experience some horrible missing and backfiring with my renix. It acts as if the timing is just completely out of whack. The solution I have found is: with the engine off, unplug the wire clip connection to the CPS and then plug it back in. This seems to cure it. This can also be the cure for a renix that won't start at all.

Thanx for the input, I'm hoping to get it nailed down before the old 88 leaves me stranded someplace.
I did blow backwords through the MAP vacuum feed, I could have dislodged something.
Seems to be running just fine now, maybe it's just getting old and irritable, like it's owner.