Vac Leak? or other?
 

Ok, after searching out a few other threads, I always hate to start another one................
My 2001 F150 4.6 4x4, has a really bad rough idle, loss of power. Using Autoenginuity software, bank 2 senor 2 is showing a constant .92 voltage, the others seem normal at .2 to .7.
At first, when I bought the truck, it needed a Fuel Pressure reg. the idle air was clogged, cleaned the port & replaced the valve. Tried a new O2 sensor in B2S2, but no change. vacuum gage at the intake indicates "retarded engine timing". Also cleaned the throttle body & Mass air units.

Any help would be appreciated.

Thanks,

NT

I would check the wiring to the O2 sensor.

There's probably nothing wrong with the sensor or it's wiring. Ignore it for now, it's just reading what is present in the exhaust stream.

Several thoughts come to mind:

Severe misfire.
Severe vacuum leak (check PCV system first!).
Restricted converter on bank 2.

Thanks for the responses,

I thought about the wiring, I have checked as much a I can, but don't see anything abnormal.
The Autoenginuity tells me there is no misfire, The PVC line hose was getting soft, so I put a new Ford OEM unit on.

How can I tell if the Cat is clogged? This truck has 4 cats, the rear cats have the O2 sensors in them.

Thanks,NT

Did you actually go in and check misfire counts in mode $06 or just "scan for codes"?

That would be backwards from where they would be expected. They should be on both sides of the converter closest to the exhaust manifold.

Remove the upstream O2 sensor and see if the symptoms go away and the vacuum readings normalize.

Sorry about the delay in responding, the site kept telling me to reset my password?????

In AE, I will need to find the $06 function to check for misfires. Any help on where it is ? Yes, just pulled codes, but did the KOEO & KOER functions.

Thanks,

NT