... related threads and many of the symptoms descibed in those seem similar to mine, so I'll be inspecting the wiring from the sensor to the PCM (to include the ground for the PCM).

However, I just wanted some input about some of the symptoms this truck is experiencing. On 3 different occasions the truck lost AC and Tach while the truck went into a "limp mode" where it was described to me that the truck had little-to no power. Now, I've sold the truck in my signature to my son so he has been driving it for the last few months, but the first time this happened my wife was driving it and the 2nd/3rd time, my son was driving. On the 1st event my wife said she first noticed that the AC was not working and then the engine had no power; she said the CEL was flickering.... NOT flashing. She didn't say that the tach was not indicating, but she just might have missed it. When this happened to my son he noted that the tach was not working AND in addition to the CEL flickering the Wait to Start / Water in Fuel / Trans Temp lights all flickered too. It was stressed to me that the lights were flickering, not flashing.

On the 1st and 2nd events I went to recover the truck; each time the truck had been shut down for 15-30 mins. In each case I couldn't get the truck to duplicate the problem. The one thing I did notice was, after each event the AC blew WAY colder that it did normally.

Does it still seem like I need to inspect the wiring from the ESS up to the PCM or could I have more than that going on?

Thanks

 

I think you have more going on. The engine should not have a 1/2 power limp mode.. Its mechanical so to me it sounds like you are loosing power to the fuel shutoff solenoid / relay and its causing it to shut down. This may be due to poor contact at the battery, a corroded blue wire at the battery or an ignition switch failing to make contact. Something is loose/worn.