So the truck out of no where today pegs the temp gauge. Pull over expecting to see a hose busted, but nothing. So I figure must be the T Stat, replaced with 170... test i drive way holding at 2000 rpms with a/c on, all is well. Take it for a spin and same thing, pegged gauge.
The gauge will go middle of the gauge, to ice cold. Then it will creap up to middle (norm temp) and then peg hot. Open the hood and it doesn't seem as if the truck is as hot as the gauge is reading. Kicks codes P1299 and P1209. REALLY driving me nuts...
Any insight? Air in system, fan clutch, water pump, sending unit..? I am open to anything guys.
Is the sending unit on the front of the driver side head..?
Thanks in advance.