[V8] No ECU, messy running..

[Coleman, David]

To follow up on yesterday's "crappy running in crappy weather" ordeal:
Recap -- after driving in heavy rain for a bunch of miles, the car started exhibiting various levels of hesitation, bucking, farting, and general wacky behavior.  Put it away in the garage for 24 hours.

Last night I made sure the TPS plug was dry and drove around the block.  No problem.   But an hour later, the same troubles from the day before came back.  Three main points to be made after diagonsis:

1)  TPS plug was dry, although showed signs of having been wet.  WD-40, compressed air, repeat 20x.  It's now drier than this list's sense of humor.   :-]

2)  Code Retreival:  Inop.  I was using my little LED w/ jumper wire setup, which has worked countless times in the past.  But now it just glows red, and won't start any code blinking sequence.  Fuse #4 OK, +/- in the first black terminal confirmed.  Still working on confirming continuity w/ other terminals and corresponding ECU plug wire.  This malady has me especially concerned.

3)  All sorts of intermittant failures:  Car sometimes starts, sometimes not.  Runs VERY rich and at various levels of crappiness when it does.  Right side distributor SOMETIMES has no spark, oil pressure warning comes on SOMETIMES, Fuel pump relay is clicking like mad, and running/starting behavior is affected by jiggling the reference sensors, the oil pressure plug on the r/s block (isn't that the gauge, not the lamp?), and the ANTI-LOCK OFF light stays on when the car does decide to start.

I've confirmed good dist. caps and wires (via swap),  reference sensors are new, O2 is new.  Tonight I plan to remove the belly pan and see what there is to see.  I also will look for bad ground conditions.   But this one's starting to get away from me...  Questions to get me going again:   Does anyone have any idea why I'd have trouble communicating w/ the ECU, i.e. get no codes?  What do the two semi-heavy brown wires bolted to the rear of the left side of the block ground??   Generally, WTF?

Any insight would be greatly appreciated!

-DaveC.
'91 V8 5M