With the engine at #1 TDC, the trailing edge of the rotor should be .020" PAST the #1 terminal in the cap.
They may have fixed that by the 89 model year. A TSB says that is the ideal spot. I've never had an 87 or 88 that actually ended up there. The ECU will adjust the timing over a pretty broad range almost to the point of the rotor being one plug off at initial setup.
Lets rehash, sometimes a person gets tunnel vision. Losses the thread, with all the spot checks on sensors and stuff and gets confused.
The main goal is to narrow the problem down to a sub system.
Open loop, closed loop. People like to think it is one way or the other, but the system kicks in, in stages. Open loop, the system runs pretty much on default settings, from the sound of things you seem to be doing pretty good at the default settings, then the system screws up.
One of the first things that kicks in is the O2 sensor, or so it seems to me. The heater heats up the O2 sensor it starts inputing. O2 sensor controls the IAC at idle. So it seems probable either the O2 info is wrong or the IAC is acting up. O2 sensor is bad, the heater is bad, the wiring is bad.
IAC, low voltage (weak battery) and they stick, full of dirt and they stick, they can even stick because of semi solid junk behind the IAC piston. They work by adjusting a little too lean and a little too rich, then ECU picks the just right spot. Sounds like yours may be closing in stages and choking the motor. and/or you have vacuum leak on one end of the intake or the other, the O2 sensor is closing the IAC trying to adjust and leaning out a few cylinders until the motor stalls.
Unplug the EGR vacuum line, squirt a little penetrating oil on the shaft, reach in and twist the shaft a little with a pair of needle nose pliers. leave the vacuum plugged off.
Unplug the IAC when your idle is good. Or you can even unplug the IAC and then adjust your idle at the throttle plate stop. Run it for awhile (15-20 minutes) then check your plugs. The soot covered plugs are likely air starved, the mostly clean or white-white plugs are likely lean. Bone white, light grey or even brown tinged are close.
I've never tried it, but what the heck, unplug your O2 sensor. It is likely to default to open loop.
These steps may help you narrow it down to a specific sub system. If it operates in open loop and not in closed loop or one step in the closed loop transition, you can then start checking one sensor at a time, first the sensor, then the wiring for that sensor.
Better than half the problems I've found are in a connector, a splice or a burnt or chaffed wire someplace. IMO many sensors get changed that aren't needed. A couple of TPS, a couple of CPS and a few O2 sensors are pretty much all I've ever changed in 25 years of Renix. I have a junk yard set for testing, but most times it ends up being the wiring, a splice or a connector.
You said you modified your CPS to sit closer, may or may not be beneficial. All I have ever done to mine is make sure I use the stock bolts and shorten the CPS to ECU wires and bypass every connector possible. Mine are soldered directly to the ECU. For testing I cut the wires and use a wire clamp for testing, then re-solder.
Sometimes it helps to let it sit for a day or two. I've made myself nuts trying to figure mine out before. Two days break and I'd find the problem in the first few minutes.
The difference between a hunter and a gatherer (male and female) a guy gets on a trail, gets tunnel vision and sticks with it. A gatherer runs from clump to clump, pretty much randomly and gathers whatever is edible from that clump. Men and women are generally wired differently, different priorities.
I wish I were there to help, hard to troubleshot with some of your senses not being used, instincts are hard to convey over the internut, I amaze myself on occasion. I find my instincts to be as valuable as my reason, sometimes more so. Sometimes the little things will tip you off, hard to convey over the internut without writing a book.
You sound smarter than me and competent in your knowledge, if I can do it you can do it. I've still got my Renix and have been married, to the same woman, for 35 years, it is possible.:roflmao:
