Assume you have the I6 engine. Your code P0128? Very common on our platform, it's
your thermostat. In a nutshell, your engine isn't heating up to temp fast enough, not that
it's running cold, stat is opening up too soon, or stuck open.. To rule out the temp sensor,
hook a scanner up and see what the temp is at operating temp, should be around 195 ( or
whatever the stat is rated for). Our gauges are really bad, so if it sits at 210 or a tad above
(that's normal), likely not going to be your sensor.
To replace on the I6 engine, I remove the battery AND the battery tray, and the alternator.
With these out of the way, you have a ton of room to yank the stat out. If you have small
hands/arms, some people can do it through the wheel well. If you had an 05 or older TB,
I'd say replace the sensor too, it's right above the thermostat. BUT in 06, it changed
locations to passenger side, way in the back in the block. Pretty hard to get to.
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