Poor performance and gas mileage checklist

[Billabob]

Apologies again for the incredibly sporadic responses, I was hoping to return with a little more info but a pesky rear main seal leak has taken up all of my free time. Thank you Ohm for the info about the shielded wire, that confirms my suspicions about it being intentionally bare. A quick glance with my trusty timing light revealed that my engine sits at 20 degrees at fully warmed up idle. I'll be giving my CPS a closer look in the near future and I have a good quality replacement in case the current one is busted, might be a good time to do C54's timing advance mod while I'm at it. My immediate focus will be on the MAP hose as mine is leaking worse and worse while my LTFT is still rising, currently in the high 160s. All the parts from Cruiser's tip #31 have arrived but still waiting on the obscure 1/8" NPTF tap to come in. Hopefully that should solve a few issues at once. Lastly, I seem to have gotten to do the bottom of my temperature sensor woes. My dash sender reads 225 ohms of resistance at operating temp but only reads 150 degrees at the dash. I believe this sensor is working properly but has faulty wires or dash gauge. My CTS on the other hand only reads 438 ohms at operating temp and the temperature reading on the REM reader reflects this value. I believe this sensor is faulty but the wiring side is working properly. I also have a good quality replacement sitting on my desk, just need to find the time to drain the coolant. Again.