I have a 2002 3.7L Jeep Liberty, blew the head in it and put another motor in it. We have had it replaced the computer, all the O2 sensors. It would idle rough and stall out with reducing speeds, like when turning corners. Changed the power steering sensor, it was still acting up. Just changed the PCM and now it will only run for 30 seconds then die. Code P1685 is coming up. Any suggestions on what to now? Any help would be greatly appreciated!