Alright, so I had just picked up this 93' Is400, it had a rough idle and would turn off, misfiring, yk the usual. Threw me tps codes so I inspected and cleaned the throttle body and everything looked fine. Turns out the ECU was leaking on multiple capacitors, so l picked up a new ECU from someone off of marketplace just today, all the capacitors have been replaced and is in great condition overall. I put it in and now my car won't rev past 2000rpm and has a check engine light. Pedal all the way to the ground and it struggles to get past 2000rpm. Took it for a drive and it just won't rev up at all. It Idles just fine too. Not really sure what's going on since these problems only happen when I put this ECU in even though it’s been repaired and in good condition. Anybody know how to fix this?

 

There's a lot of threads on this if you view the search. Your car is in limp mode

You mentioned you have TPS codes. I imagine you still have Check Engine codes now. Are they the same? It's probably the cause

Check out these threads -

https://www.clublexus.com/forums/ls-...l#post10620320

https://www.clublexus.com/forums/ls-...2-000-rpm.html