97 Nissan Hardbody Manual RPM Issue

[jakestg]

Hey,

I am just asking if my engine is running properly? Rarely in the mornings when I drive and get to 15 MPH I shift into second. I usually shift at 1900RPM and continue shifting and so on.

Now when I drive the truck it goes all the way up to 3000 RPM quickly and gets to only 10MPH. I cannot shift to the next gear below 3000 or it will sound like i'm undergeared and making the vibration noise. My gas mileage is horrible, I get like 12 Miles per gallon on a full tank (15.9 Gallons). My truck Idles at 1200RPM and sometimes the RPM will fluctuate. Is this the normal operating RPM?

I got a new air filter and oil change.

Thanks

[DeltaP]

Sounds like the clutch is slipping. Also 1200rpm at idle,parked,out of gear is too high.