Okay I know this is long but I wanna be detailed, I have a 1997 Dodge ram 1500 4x4 5.9 360ci when I start it after it's sat for thirty minutes or longer it idles rough not a low idle just kinda loopes like a cam if I rev it once or twice it clears right up I've owned three previous trucks all 2nd gens 2 5.2 318ci and one other 5.9 360ci none of which have done this, I've replaced the plugs wires cap and rotor ignition coil made sure the wires were routed properly I've also replaced both temp sensors along with cleaning the throttle body replacing the map iac and tps sensors and even the iat sensor it plus checked the intake for the pleuim issue along with a vacuum check all checked out well I've also replaced the upstream 02 sensor to just cause only sensor I haven't replaced is the crankshaft position sensor only modification I have are cold air intake but it's a Spectre worked fine on all my other trucks and a cat back exhaust with a turn down mid cab any information and help would be much appreciated im at a loss at this point .

 

Possibly a leaky injector or two.... Does it make any difference if you leave the front O2 sensor unplugged?

 

 

time ta whoop out a scanner capable of live data stream. Check your long n short fuel trims, O2 sensor readings n take especial note of the throttle position sensor after initial startup. Does it give a different reading after the vroom, vroom?

 

 

TPS volt readings will change when you depress the accel pedal. That is how the ECM knows something in his universe of engine control/monitoring is happening. What I mean is, look at the volt reading at idle before AND after the varoom manuver. Are they roughly the same or are they different, n if so by how much?

 

 

 

If you still have the old TPS, put it back in n see if it clears up. All the TPS is, is a wiper based varistor (resistor). If the new one has a bad spot where your idle is set, it could cause a rough idle. It's the "clearin' up" after a vroom, vroom that is curious. It could also be the idle air control, ya gotta approach this as a "system", not just a part. Not sure what HAL tells the IAC to do on startup; warm or cold??? Does HAL say...open wide, then adjust for idle? Does HAL say, just sit there cause you were built by union workers and live by union rules? Maybe you got some dirty connector on the TPS. check your wiring to the ECM.