I now have the intermittent loss of power, falling tach, stall, then easy restart after a minute or two scenario on my b230f regina 93 944. Having already refreshed the fender grounds I replaced the RSR with no change in symptoms. I also cleaned and tightened connections from coil to power stage and swapped in a junkyard one with no change. Further testing of those passenger fender grounds reveals 2 ground wires entering the harness and heading to the rear of the car that show very low resistance to ground when disconnected from the fender grounding point and one wire that appears to be heading to the front of the car with infinite resistance. This doesn't seem right to me.

Other possibly unrelated details:

-headlight relay hot to the touch (tried another one - hot too)
- occasional lurching while in cruise control mode at highway speeds (worse after wet conditions)
- engine starts immediately when cold or hot (except when it stalls as described above)
-acceleration normal
=block mounted distributor
-fuse block connections show no signs of corrosion

Any thoughts before I open up the harness to find out where that ground wire goes?

Ron

93 245
93 944

The black wires coming to the ground connection point provide a ground path from some component. After you disconnect the wire from the grounding path it is "floating" and is no longer at ground potential, the resistance to chassis ground will depend what it is connected to at the other end.
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David Hunter

I haven't done all the mental work on 12V wiring that I should probably do at some point. I was sure I'd read somewhere that to check the continuity of a ground, you disconnect the ground and the negative battery cable and check resistance. I need to sit down with a magnifying glass and some schematics and get a better grasp of what I'm testing for.

I swapped in a different fuel injection relay yesterday and had no stalls in an hour of driving but not enough data yet.

Ron

Glad your appear to be running OK
Better get out that meter and play with grounding because that method sounds fishy to me. Perhaps it was part of method to detect a short to ground. The low current in a meter will not always show resistance in a ground path.
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David Hunter

The black wires coming to the ground connection point provide a ground path from some component. After you disconnect the wire from the grounding path it is "floating" and is no longer at ground potential, the resistance to chassis ground will depend what it is connected to at the other end.
--
David Hunter

"...the intermittent loss of power, falling tach, stall, then easy restart after a minute or two...

Often times this is indicative of a bad crank position sensor.

Any fault codes recorded in the OBD?

no codes
new CPS.