Disabled O2 Sensors from used car dealer.

[RKB713]

I recently purchased my 2009 Expedition EL 4x4. On a test drive motor seemed sluggish so I checked codes and found they had reset battery ( as usual ) but the VCT / phaze codes were pending. Looking under hood appeared to be new valve covers, few non oem zip ties, and new VCT sensors. I was concerned that it could be the timing mess the 5.4 are know for. Used car dealer said they would fix it before I bought. I can back 3 days later drove and was 90% better had a stumble on the 3/4 throttle transition. No codes pending. After driving a few days i noticed the start up exhaust fumes were rough, first 30 seconds or so as well as exhaust seemed slightly louder for same time ( weird). I broke out the trust code reader and found they disabled the O2 sensors some how.

Question, could disabling the O2' s trick the cam/ timing issue?
I want to enable them but am afraid the timing problems will return.

Next issue, The electric clutch fan, yes its electric to engage then standard clutch. I see it was only use 1-2 years then followed buy full electric. My A/C sucks, proper pressures when fan 100% which is almost never. I swapped to 2010 electric fans and universal fan controller, this helped the a/c a bit but now has codes for voltage and signal return. Does anyone know a way to use a resistor, or disable that option? I am considering a 2010 ecm as well.

Thank for the help

Btw Florida here, no emissions, plenty need for A/c

I will return with exact codes asap.

 

[GlennSullivan]

A dealer disabling an emissions control device or selling a vehicle knowing the device is disabled is a Federal Crime.

When the vehicle first starts the ECU is in open loop and running off internal code and ignoring external sensors. only after a period of time should it switch to closed loop and start taking input from external sensors like O2 sensors, so whatever is happening on startup, it isnt from lack of O2 sensors, probably part of other changes to the tune made when the 02 sensors were turned off.