I recently purchased a em1, it has a aftermarket fuel rail and im pretty sure its making the car run terrible(low idol, stalls a lot when I first start it), but im not sure because im kind of new to the Honda world, any help suggestions or tips to correcting this? or is it something completely different causing the problem?

 

Stock engine and ECU? Other mods?

Rail details?

CEL codes?

 

Stock motor and stock ecu, it came with a after market ecu but it runs even worse when I have that connected. But other mods include apexi exhaust and some header, some intake. The codes it's throwing are

P0122 throttle position sensor
Po141 02 02 heater circuit, o2 sensor
P1106 manifold absolute pressure sensor
But to be honest I don't know what any of them are other than the 02 sensor