I have seen many threads on this but this seems a bit different. I replaced the hp-22 and transfer case in an 01 with another of each out of an 01 which I don’t recommend trying alone. Replaced the battery and now it starts revs to 600-800 RPM and dies immediately. Fuel pump is working I removed it and tested it on the bench, should I start with an inline spark tester then start looking at bad parts. Before the swap it started and idled great. I have put 8 gallons of 91 octane and a bottle of sea foam in the tank.

 

I locked it with the key after working on it one night and unlocked it the next morning fired right up. Now it won’t go into gear.