My 03 dodge diesel wont run unless the rpms are 1000 or higher

Have you checked the fuel pump for any blockage? The car isnt getting any gas unless u manually pump it by pressing the pedal.. So start there
Sometimes when a engine requires excessive revving and throttle to stay afloat its a fuel supply problem. A clogged filter for example can be overcome with excessive throttle that drives the fuel pressure up enough to force it through, but it will barely trickle at idle and stall.

Usually the dead give away for fuel pump is when someone complains they have to floor it as soon as it turns over or it will die right away.

Automatic transmissions need to have a higher idle speed on the motor because of the load put on them by the transmission. You may have set it too low. 780 might be the idle speed with the transmission in D and the brake set.

There are none

The transmission is burnt-- you said it

Has to come out & be rebuild or a reman installed

You new that-- right?

Better check the water separators and fuel filters. Also may have lift pump going bad

likely your throttle position sensor or idle air control valve. Try disconnecting each one when the problem starts if it corrects you have found the culprit.

check cylinder compresions,sounds like there low(worn rings)by the way the 5.7iroc is one of the worlds best engines.....

You need to clean the throttle body, and possibly replace the Idle Air Control (IAC) motor. Use a baby bottle brush with nylon bristles and some carbureator cleaner to clean the throttle body and the back of the throttle blade. Take intake hose loose from engine have someone in car hold gas pedal to floor( engine not running) spray carb cleaner into throttle body and brush with bottle brush. When clean re attach the hose (engine will not start with hose un hooked) and start the engine. The engine might be hard to start the first time because of the extra fuel in the intake, but it wil start. You will need to run it a few minutes to clear the extra fuel, then try the ac and see if the idle is better.

dear friend-your problem might be the crank angle sensor as your problem is intermittend.your vehicle goes into limp mode.i suggest you take this vehicle for a diagnostic
test to find fault codes

yes it does if it is reading lets say lower than normal that would explain easy start up and stalling later.the coolant temp sensor has two wires .so if your car warms up and your coolant is about 200 degrees your coolant sensor might say 80 degrees .access to a scanner to check temp would be great.

I would suspect water in the gas...check with nappa they sell an aditive to disolve the water..other than that the tank will have to be drained. Gas floats on water,so the water if there is any will be sitting in the bottom of the tank, you could remove the filler pipe and push a hose in and pump the bottom of the tank, with an external pump.