Chrysler Aspen idling bounce
 

Hey Guys i have a 2007 Chrysler aspen 4x2
I have been very pleased with the truck until now.
I have been having a issue with the idle. It will normally idle around 5rpm. but lately it will "bounce" between 5 and 10 and you can feel it going up and down. it will happen for a while and then sometimes stall out. it will start right back without a issue most times a very small amount of times it will take a few tries to start.

I took it to my mechanic and he said he couldnt find the problem. This is my wife and kids daily truck so i need to get this fixed asap

Not sure if this has anything to do with anything but I get the check engine issue a very few times its always the gas cap is loose error. My wife said she puts it on right but it never happens when I put gas in.

Could be the Throttle Position Sensor.

Is the code P0457 or P0455?

If it's P0457, loose gas cap. If it's P0455, something's up with the Evap purge system. Sounds like the latter given your other symptoms.

Idle air control valve
 

Took me awhile to discover that this was the problem on our Aspen. Tach would 'bounce' around like you said, especially at traffic lights, drive thrus, etc. replacing the idle air control valve did the trick! Not expensive, easy DIY job :)