jimd95ta

car started out as a v6 but i blew a headgasket and replaced with a lt1 and 4l60e trans had them both gone thru b4 installing it also had a pain free wiring harness and the computer is out of a 94 caprice classic water pump is working no air in coolant fans both working. seems to be a computer issue on the trans takes off the first time in 1st fine but will not down shift from second even if you try it manually it has a obd1 connector any ideas ive tried a different computer still same issues thinking its going into a limp mode but the car did have a 2nd gear start button where the traction control button on the v8s are does not matter if i press the button or not still wont take off in 1st gear after the first shift any ideas thanks

Tinbender59

ist problem is get the right ECU, with the right program second did you use the V6 radiator, if so get a v8 radiator. start there.