I got the new coil installed today; this along with the new GM module in the Lucas "Magic $800 Box" I hoped would cure the C-H-D Syndrome. Well, she started right up, and idled very nicely. I decided I would go to town and get some gas: 5 miles. Soon as I put it in reverse, it died. It started right up and off I went. When I stopped at the next intersection (almost there) it died at the intersection. This is the first time I recall this; formerly it would not restart after a drive without multiple tries with the C-H-D.
This time it seems to restart much more easily, and with fewer tries. Also, adding a little throttle seems to help it restart, where it never seemed to help before. I don't know where I am going with this next: maybe the idle air valve? Also, I have checked every ground I could find, but the one on the ECU in the trunk.
The car just runs so good when it runs: no stumble, etc, that it is a little perplexing that it keeps dying.
Also I noticed the coil I removed had a label on the underside, with a date of 2003 on it, so it was not the original coil. It has a chip on the plastic + tower but I don't know if this would cause trouble.
I plan to change the coolant tomorrow: I bought 2 gallons of Zerex G-05: the label on the back indicated it was approved for Jaguars of my car's vintage; i.e. older ones, so I decided to use it rather than the "fits all cars" Prestone I already have.

Sign me "marching on"

 

Perhaps this has already been mentioned but is the throttle body clean and the throttle blade set at the proper .002" gap?

What's your idle speed?

A thread from a couple weeks ago covered something similar. Might want to read some of the replies. I think it was titled "Stalls in gear" or "Stalls with A/C On" or similar

Cheers
DD

 

I did check the throttle body earlier with a feeler; the gap seemed about right. I wiped out what I could with the throttle plate held open and it wasn't particularly dirty, but not white glove clean either. Should I remove it and dunk it in cleaner?
The idle speed seems a little high at just over 1000; I don't know if someone adjusted it previously in trying to get it to stop dying, or what. I did notice that, after I installed the coil, when I started it, that is the first time I noticed it idle at just under 1000, according to the dash tach. When I garaged it that evening it was just over 1000, though. I am still looking for air leaks after I found the vacuum advance hose rotten on the end. I am reviewing the previous posts regarding this topic as well; I will be able to go in deeper this weekend, than I can on evenings after work.
Thanks!

 

If it was idling at 600-700 I was gonna suggest bumping it up a bit....as these engines are weak at low idle.... but 1000 rpm is plenty.

Throttle body does not have to be white glove clean. So long as it isn't outright gunked-up it should be OK and you can focus elsewhere.

Here's what I would do next. Run a jumper wire from the battery "+" post to the coil "+" post. Start engine, drive car. See if anything changes.

Carefully inspect the wiring/connection at the coolant temp sensor. Repair if it looks flakey. If the connector looks OK, use a thin paperclip to jump the terminals inside the connector. Drive car, see if anything changes. Do this on an already warmed-up engine.

Do a good, careful check/clean/repair/tighten routine on wiring/grounds/connectors related to the firewall relays, coil, air flow meter, etc.

Cheers
DD