1999 3.8 T/C. replaced engine with used one. Used the original wiring, coil pack, etc. The original engine started fine for weeks but not driveable After several attempts to start this used one it runs ragged and as long as you give it gas in a stationary position. The ac which was ok now is not cooling when I finally get it to run. The cruise light is on. CHecked continunity of wiring and plugs and coil pack ok. Tried to get a diagnostic code but nothing never shows. Have a 97 Voyager and codes pop right up. I have removed the battery to try and clear any codes but still nothing. Also notice the radiator fans not working but don't know if they were before. I assume that they were. I have checked all my wiring and hoses and man I am lost at this point.
When I try and start it after I release the igintion it acts like it wants to start when the ignition goes back. It make take several trys to start and sometimes not. Any thoughts and help appreciated.

 

I had a defective crankshaft position sensor which corrected everything but P0171 lean mixture bank 1. Van running smooth with this code.

 

It's possible these two engines have different flywheels and the crankshaft position sensor is not giving the right signal for the ecm.