Hello to all who are receiving this distress call and many thanks in advance for any suggestions, Im Steve and Im bummed. 2000 sonoma, 4.3, auto, 2wd, 298000k. truck died while driving, by the time the wrecker arrived battery was dead, towed home and recharged battery and it started up perfectly as usual. Installed new battery as the old one was, well, old. Will not start. No security issues showing, has spark at plugs, fuel pump pressure shows 65 lbs and within range for holding pressure time. Had a mechanic take a look and without proper test equip did what he could, propane in pcv engine fires but will not run, his conclusion was ecm not supplying ground and it should be checked, rolled the die and got a new unit flashed and installed, relearned the fuel key etc and sure enough... no start. Did have ignition cylinder issue a while back so installed a new cylinder and key, redid the relearn and still no start. Questions 1) Ive tried to relearn the fuel key again but the security light goes off and stays off, cannot find a reference for this anywhere, does it mean the key is learned? 2) temperature sensor? Im hoping to get a code reader tomorrow and check that. Thanks!