Got a couple questions on truck I bought recently?

[stimo]

I just bought a 01 diesel and I have noticed that the rpm's or off for some reason and cant figure it out. At idle it runs 375 rpm's and I know that is wrong and also running at 60mph in overdrive is says 1000 rpm's. What could be making it read that I know it is running more rpm's than that. Truck does have 3.55 gears. Also truck is running at 160* so I'm guessing the thermostat should be changed to a 190*. I have heard the 190* are better to run in these trucks. This is just a daily driver truck also. Not looking to do anything radical to this one.

 

[scott2001]

somebody may have pulled the needle off to put in one of those aftermarket guage covers the ones that turn them white. if they didnt follow the instruction close that may be whats wrong, the got the needles in the wrong place when they reinstalled them

 

[4x4dually]

Find someone with a handheld to plug into your diagnostic port. It will read the RPM's from the ECM which should be accurate. If the needle is in fact the problem, then you can use that to adjust it properly. But, you could find a faulty ECM, but highly unlikely if it is running properly.