00 Civic DX with just a header. in and out power
It feels like the power goes in and out on my dx. Ive changed plugs, wires, cap, rotor, coil, and radiator (bleeded air out already). Also have ran sea foam and cleaned off iac valve and cleaned throttle body. New air filter and new oil. Just bought the car and it only seems like it is in 3rd 4th and 5th gear. im stumped. Could it be a timing issue? I never adjusted the distributor and marked it exactly where it was at when I pulled it out. What else could I possibly replace or check? Timing belt maybe? car doesn't run rough at all, and it seems like it only does it at warmer temperatures later on in the day(put it in 5th gear and it starts losing speed and have to down shift to get it past a certain speed to put it back in 5th)! Morning it runs fine. Idles at 700-800 rpms. Codes read for engine misfire im assuming because car is missing secondary 02 sensor due to previous owner replacing factory manifold with aftermarket header and not putting a secondary back in it.

 

Post the actual CEL codes. If you reset the ECU, do all the same codes return?

 

Well if it's a dx the previous owner probably just put the secondary 02 sensor in the slot for the primary 02 sensor which would definitely cause some problems.

Make sure you are not getting a code for bank 1 sensor 1 oxygen sensor, if it has a header on it the primary sensor gets moved down line back under the car and you have to loop the primary oxygen sensor from the front of the engine to the back of the engine