Need help with diagnosing IAC

2005 Ram 1500 4.7. no codes idle jumping up to 2000 rpm in any gear , due to IAC but if I snap the throttle or if I tap on the throttle body it sometimes goes down . spayed brake clean looking for vaccum leaks found none ,tested with a snap on scanner it lets me control the Iac also reset the iac it corrected it but started acting up again, tested with a scope an it shows an intermittent erratic waveform that sometimes is dropping out.I believed it to be a shorted coil in the IAC valve and replaced it to no avail. what an I missing. Thanks for the help in advance ,also shifting problems intermittently like its not finding gears mostly after stopping at a light .

Take a look at your tps voltage on your signal wire or tps% pid my bet is it thinks your at partial throttle and it's trying to get the rpm up to the desired throttle position assuming you don't have a vacuum leak

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I checked the tps pid and it looks good

What is your IAC step count when this is happening?

jerry r wrote: tested with a scope an it shows an intermittent erratic waveform that sometimes is dropping out.

Can you post a waveform of this?

You said tps pid looks good what was it's %?

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it ended up being the tps thank for your help

Glad you got it fixed. for reference what was the throttle % closed throttle

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when it acted up the tps % was up to 20