1jz limp mode?
 

I am lookin at buying this supra off CL, dude says it has a 1jz but wont run out past 4grand on the tach. So i did a few searches on here but im mainly finding stuff about the 7m, How hard is it to diagnose and fix this limp mode on the 1jz's, i have no idea what all mods are done because its not mine.. (yet :D). ima keep searching the site to see what i can find, i normally wouldnt repost a thread is already been answered in the past im just kinda in a hurry to get a offer on it before it passes by. thanks :D

Start with checking for diagnostic codes stored in the ECU, inspect for cracks or holes in the intake piping and couplers, inspect the vacuum line which runs to the MAP sensor and check the wiring for the knock sensors.

You'll need to get a hold of the TSRM and wiring diagrams for the 1JZ sooner than later. I don't recall if anyone's even posted them here but over at SupraMania they've got a section specifically for swaps.