P0118 code...2006 V6 Tacoma

Running into the above code. Says its the Engine Coolant Temperature Sensor (ECT). Got in the Tacoma today and tried to start it after it had sat for 3 weeks. Didnt start after a lot of cranking. Had to shoot some starter juice into the airbox. It did a bit of chugging before it stabilized. Crazy thing was, I think it had the code before I tried to start the truck. Once the truck finally started the code stayed. Tried to do the erase on the code reader, but it continued to stay on. Harder than hell to locate. Looks to be hid way in the back of the engine by the firewall.
Anyone have these troubles?
The starting issue is weird, kinda like it lost its prime or had an air bubble in the system. Fuel was at 3/4. Plenty of coolant in the system and reservoir. Thermostat seems to be working fine. Drove the truck for about 45 minutes with no issues. Started it a few times tonight with no issues, except the Check Engine light.

Perhaps very old fuel?

Not the code, the hard start that you mentioned.

Sooooo. Digging deeper, the code throws the vehicle into a "Fail Safe" mode and limits a lot of engine functions, things like fuel. A few sites said this was a common problem after 125,000 and if your coolant if rusty. This is why I couldnt get it to start. Went out later that evening, and it wouldnt start, and still showed the code. Im planning on changing the sensor tomorrow. Will let you all know how it goes.

I wonder if the rust in the cooling system 'tells' the sensor that the engine is overheated and prevents the engine from starting and causing more damage?

The problem was found to be both wires for the sensor had been cut and badly spliced sometime ago.
To get to the sensor, you have to take the entire upper intake off, remove the pass side fuel rail input line, remove the coolant hoses that go to the throttle body, and lots of pesky wiring clamps (one hidden behind the intake below the coolant lines), and a DEEP 19mm socket, and drain a bit of coolant.I swapped out a new one since I was that deep into it, and she fired right up once bolted together. Good luck, take your time.