2012 Nissan Titan went into limp mode. Had friend at dealer run the scanner for codes. Nothing displayed. No catalytic converter code, no Oxygen senser code ,Nothing . It will not accelerate over 2500RPMS. I’ve check under the truck for burned wires, leaks, shortages and can’t find any thing. One forums discussion said check brakes. So I swapped everything out, flushed the tranny, flushed the entire drive train. Replaced the MAF and a K&N air filter. I’m lost guys , I need help. Almost ready to throw in the towel . 530$ spent this weekend . Nothing positive to show for it. Help!!!