totally out there but maybe do a battery disconnect for 10 mins making sure all power is drained then a reconnect. I am not sure but you mentioned you just changed the cat back? 02 sensor issue?

 

If you smell gas, the injectors are probably firing - I suspect you have no spark.

 

im gonna hook up my battery charger to the truck for an hour or so and try and start it again if not its going to the dealer tomorrow.

 

did u ever find out what the problem is? im having the same issue my local shop is saying it seems like some with the security system. i called the stealership and they said it might be my anti theft module. any ideas out there?

 

Try some starter fluid...