Well I just bought a 2004 TB 4x4.
So needless to say i am new to this site.
Not long after i got the truck the engine light cameon. I putthe OBD II reader on it and came up PO 128. I did my research and read the forums on this site to others having the same problem and it being the thermostate. (problems being engine light, a few degrees under proper operating temp. when the light came during driving etc.)
The only thing that is bugging me is
1. I added engin coolant to the holding tank not alot, the level was just under the full when cold line. and the light wnt off for a few trips on its own.
2. It takes 2-3 cold starts before the light comes on again after clearing it with the reader.
3. The light went off tonight on my way home long after engine at operating temp. with the guage still a few notches under the 100 degreese C mark.
I don't like fixing things that don't need fixed, and between me and my dad we are pretty handy around vehicles and knowing all this info, we believe it is the thermostat but not sure... Anyone have any suggestions???