Ive been having problems getting rid of the P0171(Fuel system too lean Bank 1) so what ive tried so far is.... Replace coil pack, new spark plugs, tested injectors, replaced o rings, new wires, pressure tested intake mani(No leaks) and reset the ecu after. I drove around around 100 miles and a cel came on again! But this time it was P0421( Catalytic convertor Below Threshold(Bank 1) and P0301(Misfire Cylinder 1). The light came on while i was idling at a stoplight after light driving.... My mods are CAI, 59mm throttle body, 4g93 intake mani ported and polished, header, 2.25" catback, and tuned with ECUFlash. Thats all the engine mods...

I know there was a recall for the p0421 code but after i got it done my car ran weird so i took it back and suposedly they undid it....But either way i have an aftermarket header installed along with a CEL eliminator on my second cat so i thought i wasn;t supposed to have this problem.... Im fricken stumped here.... Help!!!

 

anybody???

 

yeah, the 0421 was for the first cat in the header, our cars do have a recall for it. i do believe they flash the ECU for it. but since you have a new header... what eliminator? the RRM one? you may want to consider trying two spark plug non-foulers. bore one out to .5" and then screw that on the O2 sensor, screw this assembly into a second non fouler (un-bored) and put this whole assembly back in the exhaust. this has worked for almost a year on my friend's WRX.

as for the lean code... double check the tune. make sure it's %100 spot on. if you have to you can put the stock map back on (if you have it) and see if you can duplicate the problem.