Sorry taking so long getting back to this thread. Between being overloaded at work, and making arrangements to move after selling our house, AND babysitting our 3 year old grandson........ well, you get it.

If you could get a scan-tool connected to your truck and moniter the ECT sensor, you may see your problem. From what I've read, the P0118 DTC will set for low ECT sensor voltage. This can be caused by an open circuit or defective sensor, or a wire harness being open circuit. When this happens, the PCM will read the ECT sensor value as -40*F. This will make your truck run extremely rich, give you really bad MPG's, and it will run like ****. If it runs long enough like this, it can eventually clog your cats, and the O2 sensors won't like it either. You've already gutted your cats, and are going to tune out the rear O2's, so those things don't really matter anymore. But you still need to fix the root cause of the problem.

Check the ECT sensor and harness, hopefully it's an easy fix. What mods does your truck have that might have something to do with this? If you have any questions, ask away or feel free to send a PM.

 

I'll check that out, I already changed the sensor itself and haven't seen a change.
It did fine on the way home after I changed the sensor.
After I got to the house and the truck sit for a while, I went back out to move it about 30-45 minutes later and when I started it the temp gauge went all the way to 280* so I just shut the truck off and left it alone til the next morning.

Since then it hasn't done it and it's been running steady at 210*
I'll try to get somewhere to check into this further...