Engine Surges at speed, under acceleration

[bryno]

OK, so have been doing a lot of searching on my codes:

P0150 Oxygen Sensor Cycle Fault *codes* B U
P0174 Oxygen Sensor System Too Lean Fault Bank B
P0332 Background Noise Low Fault Bank B
P1300 ?
P0302, P0304, P0306, P0308 Misfires

I am beginning the trace by checking O2's first, and then cleaning the MAF.

It is a '99 DII, with a 4.6. Plugs are the champion with 10k, but will check and wires are magnacore with 60k.

When I throw the CEL (blinking), it is coming off idle with easy acceleration and only on occasion. I am thinking 02, not MAF, because it is only 1 bank of cylinders. Is this right?

Here is the weird part (at least to me). It has felt underpowered for sometime, but recently on acceleration (prob. 3rd gear) with 25-30% throttle, between 2000 & 3000 RPM's I get surges of power. The tach shows the increase by about 200 RPM for each surge. Sometimes this is matched with the ping/rattle of pre-detonation.

Any thoughts?

 

[ruditron]

how many miles on the 02 sensors? if its all leaning towards that bank id say thats your problem.....

 

[bryno]

The O2's probably have about 60k+ on them.

Would they affect the surge/increase in RPM. I usually hear about them misfiring. Maybe it is in a 'limp' and gets good reading on occasion
.

 

[Lutzgaterr]

On my D1, I have had a fault for years, however these are the sensors behind the Cat, not in front, so no performance issues. If I were you I would pull the MAF and clean it. Another option to consider before you consider throwing expensive sensor parts at this problem is find a trusted mechanic with a Rover diagnostic book. Throw him $100 and confirm what you are dealing with. Just a thought to consider.