I don't know anything about cars so here goes. I bought a 99 civic ex and the guy I bought it from had swapped the a/t for a m/t but didn't switch the ECU . He also unhooked the check engine light, I brought it into the shop because i was getting around 15 mpg and the said I have the wrong ECU! P2E-A92 is the one I have, what one do I need?

 

AEMŽ Plug & Play Engine Management ECU 99 00 Honda Civic DX LX EX and Si MT Only Not sure if you have bought one already. Its a bit exspensive, but who knows.

Maybe try some of these also: ECU Tuning | Chip Tuning | Electronic Control Unit | OCT Tuning