Engine will not run, it starts and stalls. when cold it somtimes run ok till it warms up then stalls. replaced both o2 sensors , no change????

O2 may be bad causing a constant lean fuel command thus the cold stall issue but runs when warm with O2 plugged in .

Check the throttle plate for varnish or carbon build up , clean with throttle plate cleaner . Have engine sensors scanned with a scan tool ,mass air flow sensor may be dirty . I'd tell you to check fuel trims with scan tool but you are probably not familiar with these . They show how much fuel the engine computer is adding or subtracting . Great diagnostic tool for trouble shooting engine running problems . Also a scan tool is great to check O2 sensor switching rich to lean an back to rich signal . The engine runs in open loop when cold which means the PCM doesn't look at O2 sensor data till warmed up . PCM/ECM adds more fuel till warmed . Then it will go into closed loop fuel control , the PCM/ECM watches O2 sensors . May have a vacuum leak ,check with can spray carburetor cleaner ,spray around the intake manifold an listen for the engine RPM to pick up or may even stall the engine. Understanding Short Term and Long Term Fuel Trim

P0138 O2 Sensor Circuit High Voltage
P0139 O2 Sensor Circuit Slow Response
P0420 Catalyst System Efficiency Below Threshold

First things to check and clean is the MAF sensor and the IAC valve...these two cause problems from carbon and dirt buildup...use MAF cleaner only....if this works, great, if not....

Clean trottle body....or

Check for a plugged catalytic converter...remove the O2 sensors and start the car, does it seem better? If it does change the catalyst..

You have problem with idle air control valve, it's mounted on throttle body, easy to replace.

i wouldn't be looking at the o2 sensors! look at the coolant temp sensor! when the car is cold it doesn't correct fuel & air ratio until it is warm so it is not looking at the o2's till then! if the sensor is bad and telling the computer it is warm when it is cold them it would be leaned out and run like that then when the car gets warm it's fine because the sensor is still saying it's warm! would be the opisite if it went bad and was telling the computer it was cold! that is a sure sign of the temp sensor being bad! good luck

Does the fuel line still have 55 PSI when engine warmed up? Any other codes show up?

im assuming youve done basic tune up of plugs, wires, air and fuel filters, oil, distributor if applicable (im guessing not but never owned a dodge)

if it bogs down/stalls at stops only when its hot, try a new egr valve. probably getting stuck open. if not that try heavier oil to see if its losing compression, just one step up. also,

if it runs ok after clearing the computer by disconnecting the battery for a while, probably a dying sensor (most likely o2)

if after clearing computer it still runs bad after warm up, see if it bogs down really bad when letting it warm up from cold without driving (just idle to make sure its not egr system). if it dies or sounds like its close to dead, then its probably something fuel related (clogged/faulty injector, worn fuel pump, bad pump relay)

hope it helps

probly o2 sensor, cus when cold the computer does not take into account what the o2 sensor is relaying, but when it is hot it does, try unplugging it when hot and see how it runs, it will run rich but should run ok, if it does its the o2 sensor

1. My suspicion is your electronic ignition
2. If your car is a bit old, there might be a leak through your valves
3. Distributor timing gear is damaged (replace)