Has anyone had these codes? PO135 is for pre-cat O2 sensor I replaced both post and pre sensors so next step is to check the circuit fuse (where is it?) PO455 is a EVAP leak so I need to know where the purge or vent solenoid is or where the most likley vacuum leak at the engine will be.Any Ideas?

 

Found my evap leak under the jeep. The little rubber boot that comes off of the rollover valve from the fuel tank to that little box under the drivers side.

 

on my 1998 it was under the hood next to the batery. a 15 amp fuse was blown... my light went out when i replaced the fuse but came back on......After this I found the fuse ok. but had not look under the engine and found the sensor from the exhaust pipe was un plugged...... fuse is good but CEL light is still on fuse is still good .....With this sensor bad will it give me bad gass mileage.... now it is running real peppy and but dont want mileage problem

 

just check all the vaccum lines for cracks and for the o2s did you clear the codes after you installed them