So I just installed my new tomei catback today and did some spirited driving. Everything was smooth wasn't driving it too hard, just breaking in exhaust. All of the sudden I was at a red light and around 4th or 5th gear it felt like I had no power and when I tried hitting acceleration I didn't gain speed.. It seems like 1-3 is normal but after that it has no pickup. No engine codes as I went home and turned it off right after. This was hours after exhuast was installed.. Transmission never had any TSBs done and I'm hoping my trans isn't gone.

2010 g37x coupe 7at with 91.500 on the clock.
Not sure if it had a flush done in the past.. as I bought at 80k.. what should I test/try before assuming my tranny is gone? Thanks.

 

Sounds like exhaust leak on one of your gaskets check all bolts

 

Ok thanks hoping it's just that.. when I had no power in 4th and up it never slipped or eventually banged and caught into gear so hoping that's it..