1999 Crown Vic LX Misfires & Oxygen Sensors

I have a 99 Crown Vic LX which is throwing the following codes:

P0174 System Too Lean (Bank 2)
P0171 System Too Lean (Bank 1)
P0307 Cylinder #7 Misfire Detected
P0305 Cylinder #5 Misfire Detected
P0303 Cylinder #3 Misfire Detected
P1131 Lack Of HO2S11 Switch - Sensor Indicates Lean
P1151 Lack Of HO2S21 Switch - Sensor Indicates Lean
P0136 Heated O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
P1415 Air Pump Circuit Malfunction


It normally runs like a dream with 215,000 on the clock. I am losing power. I have new plugs and ignition coils on all 8 cyl.

I am told that I have an oxygen sensor problem but, how do I know which one? I don't want to spend $60 for a scan but, the free scans at Auto Zone won't tell me which one is the problem. The sensors run $40 or so a piece but, I just want to replace the bad one for right now.

It's colder than all get out with snow on the ground so I am trying to find the "easy button" on this. Is there one?

Are the oxy sensors easy to get to or???

Thanks!

P0171 and P0174 indicate excessive air into system---possibly an air leak. Check hoses and gaskets::::also, both together could be a MAF that needs cleaning.

The oxygen sensors are two per side. Closest to the exhaust manifold is #1 and reads air flow;the one furtherest away is #2 and measures leanness.

Try cleaning your MAF with brake cleaning fluid spray first. Then start checking for a leaking hose or gasket (the engine will speed up when the starting fluid is sucked in.

Thanks jdmeaux,

I am going to go ahead and replace the up stream oxygen sensors as they are the originals and at 215,000 miles I surely got my money's worth out of them.

I have suspected a vac leak but, never felt I could hear anything becasue of the engine noise. I did pop the plastic cover and do a visual from above the engine compartment but...that leaves a lot of uncovered ground.

Any other tips about finding vac leaks?

Have a great eek and thanks again!

John