I finally have my Frontier on the road after new head gaskets, timing chains, cats and myriad other small parts. I had an issue with the plenum (cracked) so I replaced it. I took it to the dealer to have that diagnosed because it wouldn't idle down and I couldn't find the vacuum leak. While it was there they put it on their analyzer and set up the timing and idle rpms. Ever since then, when it's warm and it sits still at a light or in traffic, the idle will drop to about 575 and the motor will idle rough. In addition, the oil gauge arrow will drop to the lowest allowable point, almost right on the white line indicating minimally acceptable pressure. My reading here tells me the idle should be bumped up to about 750, not 650 that the dealer set it at. The technician there refuses to up the RPM's claiming 650 plus or minus 50 is the correct parameters. My research indicates that the 05, 06 and 07 4.0's could have the rpm at idle changed without issues and 750 is not out of line. I've also read that there are apps out there that would allow me (Car Gauge Pro), using an ELM 327 or STN blue tooth device, to connect my phone or computer and make that change. I have also read that the Android phone can pair but the app is not compatable with the iphone. MSS3Y is someone who seems to have done this procedure and I'd like to talk with him, or anyone else that can help me find a way to change those idle rpm's. I have an iphone and a laptop, bluetooth enabled running microsoft 10. Can anyone help me find an app or a way to set those RPM's up a little without the dealer?