P0301 Cylinder 1 misfire detected
P0302 Cylinder 2 misfire detected
P0303 Cylinder 3 misfire detected
P0304 Cylinder 4 misfire detected
P0031 H 02 sensor bank 1 sensor 1 heater circuit low (catless upipe caused this?)

I have a 2003 WRX with:turboback exhaust(no cats), uppipe (no cat), ic hoses, vishnu unichip, bov, K&N air filter, and air box modified. The check engine light showed up as soon as I got my uppipe put in. I was expecting it to read the last code i listed since I still have the EGT bung inside the uppipe, but what about these misfires??????? I am so depressed. lol

 

The misfires may not be from the uppipe directly although they happened at the same time. A catless uppipe generally does not cause misfire codes.
Be sure that no hoses or sensors were inadvertently disconnected when the install was done.
The P0031 has nothing to do with the uppipe either, it is telling you there is a problem with the heater circuit for the front 02/AF sensor. Did you perhaps disturb or disconnect any of the 02 sensor wires while doing the uppipe?

 

I dunno man. I had a local shop put it in. They kept the egt sensor in my oem gutted uppipe. I tried doing the 2.2k ohm resitor mod. Maybe that had something to do with it since I had to unplug the sensor....Also, after research, i guess it is common for vishnu unichip users to get misfire codes..I dont know. I need people to help me out here. Should I worry about these? Or is it something that went off due to what i have done???

 

IS300 you havea PM

 

Are you sure you unplugged the right sensor? The 02 sensor and EGT plugs are next to each other under the black cover, did you maybe unplug the 02 by mistake?
The EGT is the one with 2 wires, the 02 has 4.

 

I unplugged the one with two wires. Anyways, I put that sensor back in after trying to to stick the resistor in to get rid of the CEL but didnt go away. So we turned the car off, waited, then took the resistor out and plugged the sensor back in. That is the end of story and I got that code....

 

Maybe you should have done a ECU reset after you put the resistor in???

 

my friend has that obd2 scanner and cleared all my codes.lol. neat lil machine.