Might be wise to add a ground to the block to eliminate any stray voltages
ECT, IAT, MAP/BOOST, and CPS all share a ground that is spliced in the engine harness,
under the intake. They are actually eng. ground but through the PCM.
"D" & "F" on the OS are also PCM sensor grounds.
Have you replaced the CPS? If not, have you inspected it?
An OEM 94 sensor will usually have the insulation missing where the 3 wires are molded into the sensor.
You said, the truck may have algae contaminated fuel?
How did you clean it.
Even if you put a Algae-cide, the dead organism needs to be thrown out.
Unless you pump the fuel out, it is still there.
That will contaminate the IP, hopefully, the filter catch it but it does not have that much capacity.
At the least the filter will be clogged.
Thank you for your expertise & thanks for the clarification on those grounds. I will confirm that they are connected and do a voltage drop test as well.The sensor grounds splice under the intake then a single wire runs to "D6" PCM. There are no bolt down grounds under the intake. You have the OS grounds correct. The source of the PCM grounds are 1- 18ga black and 1- 18ga. tan wires at the rear of the pass. side head. Time for a GM CPS.
12557046 - ACDelco 213337
It had an ACDelco in it. if it was unplugged it ran fine, plugged in it ran bad. BWD plugged in runs bad, unplugged runs good. New ACDelco is on the way... Gonna try a different one anyway. Beauty of working for a parts store. Damn BWD part is defective...LOLACDelco is the only one to use. Been there done that.