That is a good indicator you were looking at it from the wrong side, should be ten wide on one side and 14 on the other. These are all 42 pin denso computers.

 

Dang yall. I thought I had finally fixed the issue. But, sadly...the issue is back. I always had a stinking suspicion that the rough idle and rough running were related to humidity. In AZ, we have had a dry spell of weather until today. Until today the truck has been running awesome. Well today after work I started it up and the terrible idle and misfire until 3500 rpm is still there.

What in the world on this truck is so sensitive to humidity?! I pulled the kick pannel off the passenger side and the ECM and area above it are dry as a bone. The distributor has a brand new O-ring. The plugs and wires are brand freaking new. As pissed as I am I guess there is some satisfaction in knowing that the issue is related to humidity.

 

On a whim I decided to pull off the drivers side kick panel after it had been raining all day. WHOA. It was pretty moist in there and there is a lot of rust under the fuse box. The harness connectors for the rear lights was wet. The fuses for the EFI and engine looked dry as a bone when I pulled them out. That doesn't mean though that all that moisture in there isn't messing stuff up. I tried unbolting the fuse box to move it up and inspect the back but the wiring harness coming in to the top of the fuse box was pretty stiff. Right now I have the kick panel off and and have a space heater blowing toward the fuse box area to dry things out. The good news is that today was the last days its supposed to rain in Flagstaff for a long long time. I do want to address this issue of water coming in though, supposed to be a snowy winter.

 

Rain gutter seals, windshield trim induced rust, rust in the cowl from clogged drains.. (Sources of cabin water)

None of these should cause engine issues...

There is also a rubber boot for the distributor's pick up coil, not available iirc. But you can slather it in gasket goop if you're inclined.

Old dry rotted injector wire harnesses don't handle water well, nore does the ignition system and its wiring.

 

 

While you are in there, check for corrosion (also known as the green crusties) around the fuse blade contacts in the fuse box along with the wiring terminations on the back of the fuse box (and associated wiring).

A bad electrical connection, no matter where it is in the circuit, will cause problems.

If the leak has been there for a while, I would not be surprised if you find some corrosion.