im tryin to diagnose a problem with my 1997 chev blazer 4x4 automatic 4.3l i took a programmer to it and got p0102, p0340, p0440 i cleaned the maf sensor, and put new spark plugs in but, the engine seems to rev up and down when im in idle while in drive, so when i stop at a light, my truck revs up and down, and some times itseems like its going to stall.... can anyone help me?

 

Have you looked up and researched the codes in the Diagnostic Trouble Codes (DTCs) section?

 

If you unplug the MAS does it smooth out?

Hate to "guess" but sometimes it's the only option. Based on my own experience, I'd guess you did not get the MAS clean and need to re-do.

When I've had similar symptoms on my 97, I buy a can of Chemtool B-12, get the MAS out away from the car, and flush both ways thru the mesh.

Good luck