On my 06 silverado 163,000 miles. When I drove about 45 mph I saw rpm up and down 1,000-1500 rpm while I'm steady on the gas pedal so I push gas more then back on steady on my foot gas pedal it stop act. I been wonder why it cause? You have experience this before. Please let me know.

 

Did your RPM fluctuate by 1000-1500 or did it vary up and down 500 rpm between 1000 and 1500?

 

Idle 500 is normal. But I'm driving it was act up 1000 to 1500 backward forward while I'm steady foot gas pedal. So I rev up it stop act

 

So it kept going between 1000 and 1500? Does it do it at all speeds or just that range?

 

It hard to explain. When it crank up then drive on the road only a little uphill but still flat road I was cruise around 45 mph. The rpm show act up 1000-1500 backward and forward so I did push gas more then go back on 45 mph at steady it act gone. That is all I know from what I see n

 

Could be throttle position sensor or torque converter ? I'm try firgure why it cause

 

Bad stepper motor cluster in the problem is.

 

what do you mean? Can you explain a little clear to me.

 

Thats the little motor that controls the needle in the gauge you look at^^^

Sounds like the torque converter may be unlocking.

Can you get a video?

 

I tried video it was fine drive. It's hard to catch up video when it act funny. That mean need to replace torque converter?