Hello everyone.. I have a 2004 f150 new body style... I just replaced the engine with a 5.4l remanufactured engine with the cam phaser delete kit... anyways after finally getting that all put in... my truck was throwing a couple codes for the o2 sensors... p0135, p0155 active and pending...says the codes are the heater circuit for bank 1 sensor 1 and bank 2 sensor 1. I checked the fuse and it is good... I replaced both upstream sensors and still getting the same codes.. I'm not getting down steam codes but it feels like My cats are clogged from sitting for 2 years, not as peppy as my old engine and when I give her the throttle she just screams and no real jam to it... if anyone has any ideas of where to look next that would awesome..

 

I would measure the resistance of the O2 sensors, and check the connectors themselves. Also, a good old Italian tuneup can do wonders. I had similar codes, and just drove it aggressively for a bit, they never came back.

 

An "Italian tuneup" would not be expected to address electrical circuit faults which is what the DTCs indicate...

Since the VCT solenoids are supposed to powered by the same circuit as the two upstream O2 sensor heaters, checked for a botched wiring job on that modification (whatever it happens to be, haven't seen the details). You can check for switched battery voltage on each of the sensor connectors RD/YE wire (vehicle side) to see if the heaters are getting their power supply.

Of course, a botched cam phaser delete will also make the engine into a dog if the valve timing is screwed up...