Won't hold rpms. Failing TPS?

[stang0303]

I have a 2010 Suburban with the 5.3. for awhile I've had rough idle on and off. It will idle and then the rpms will get lower and then go back up. I did a test tonight by holding the throttle at different positions while in neutral. the rpms would raise and then drop by 500 rpms without me moving my foot. I have no CEL''s my throttle body is clean. could this be a failing throttle position sensor?

 

[swathdiver]

Those symptoms are usually signs of a bad Mass Air Sensor.

 

[stang0303]

Those symptoms are usually signs of a bad Mass Air Sensor.

I do have the Jr intake but stock filter. maybe try cleaning my MAS? when I bought the truck the stock filter was dirty

 

[stang0303]

I do have the Jr intake but stock filter. maybe try cleaning my MAS? when I bought the truck the stock filter was dirty

I did clean the mafs before with mafs cleaner

 

[Meccanoble]

I would take car to check for hidden codes, since its free anyway. How soon after holding the rpm does the rpm drop on its own? Do you feel this while driving, where you are accelerating then a big hesitation? How are your plugs? Miles on them?