Lexus is300 Limp mode

[Gibbs 0]

so recently my wife overheated her is300 (bad radiator cap) and the car went into limp mode. i had to change all of the front seals on the motor anyways so i did that and put a new radiator cap on it, along with a new bank 2 sensor 1 o2 sensor, timing belt and vapor sensor as it was broke. None of this stuff has fixed the problem and the car is throwing no codes sadly any ideas?

[Foompla 0]

If it's not throwing a code I don't think it's in limp mode.  Start checking the basics

[Gibbs 0]

car wont rev passed 4k and checked throttle already also just found it has a rattle in the bottom end coming off of revs....

[brian 0]

do you have any pending codes?  the IS300 ECU is insanely sensitive to things. 

[Gibbs 0]

im honestly thinking it went limp mode with the knock sensor due to bottom end rattle off rev's