I thought I did alot of research on the secondary cat thing on the 4X4 Titans. I found posts on hollowing them out, or replacing them with straight pipe or resonators. Well now that mine are there but hollow, my truck is not starting up correctly. It takes a few extra cranks of the starter to get her going, and if I try using my remote start when the engine is cold it won't start. It will crank a few times and then nothing. Maybe I messed up. I thought the reading I had done showed that no codes or problems would arise as the secondary cats are downstream of the O2 sensors. I am thinking of giving my ECU a week or so to learn the new exhaust flow parameters before I go and order replacement secondary cats. This might be a expensive screwup on my part. Do any of you fellas have any advice?