I have an S5 na. The car seems to be ok, but when i get up to 3500 rpm, 4000rpm the check engine light turns on(the engine sound changes too) and if i try to speed up after that, it's kind of difficult for the engine to do it but it speeds up. It rpm's and speeds up, with some difficulty but it speeds up slowly. It seems that something is not working right, but i don't know what might be. I've checked fuel resistor, relay,injector's resistance, everything Hayne's manual says. May be some dirty injectors? any ideas? Thanks for the help.

 

First, pull the code:
http://www.johnr.com/cpucodes.html

 

your VTEC isnt kicking in HAHAHA JK. possibly secondaries??? pull the code and let us know

 

I've done that and i haven't seen the cpu flashing. Is the cpu have a kind of led or is it the check engine light that flashes? Both of them, haven't seen it.

 

It'll flash in the dash, did you pull your battery?

get the light to flash, and then turn car off, ground green connector, turn to acc on but not engine, and then the light should give you the morse code, see the link above for more help

 

I've done that. the problem is the light doesn't flash. It turns off, 1 sec. later, turns on and stays that way.