M35 very slow

[Uberyeets]

Got an 07 m35x. 164k miles, put new throttle bodey, plugs, pcv and hose, knock semsor and harness, new cats and down stream o2. No codes an no warnings, about 23.5 sec 0- 60, slow to rev, but steady, doesn't jolt or anything. I'm bout to sell as it won't tell me what's wrong an i replaced everything I can think of

[VStar650CL]

Did you calibrate the MAF after replacing the Throttle Body, and has the MAF been cleaned? Nissan ECM's are uniquely dependent on the MAF being truthful. There's no MAP for the ECM to check against if the MAF is lying.

Did you check the exhaust downstream of the cats for clogs? If one of your fronts disintegrated, because of the conjoined Y-pipe, it could have clogged both resonators and left the engine unable to breathe. Since the cats are new, the quick test for that would be to disconnect the mid-pipe and resonators from the Y-pipe.

Have you checked valve timing? On VQ's it isn't unheard of for a jumped main chain to have the whole engine running 3~4 degrees retarded with no codes.