I've got problems. 1997 Ford F150 4x4 4.2L. Started having problems about 1.5 years ago, it was like an idol control problem. Changed the spark plugs, wires, fuel filter, coil pack, cleaned the MAF sensor, the idol air control valve and its functioning fine, and and the throttle body. It wasn't throwing any codes for a long time. The first code I got was a MAF so I cleaned that and cleared the codes. Then it was a misfire on #4 cylinder so I replaced that injector with an new one and cleared the codes. I had a pcv valve leak and I fixed that but still have problems. The truck finally started throwing codes on the problem. I thought it was pointing to a low fuel pressure condition but put gauges on it and its at 32-35 psi. The range on it was 30-45. So I don't think this is the problem but there are multiple codes suggesting this is the problem. When it starts idling hard I noticed that the fuel pressure would increase decrease with the ups and downs but never droped below the 30 psi. Please help. Listed is the codes that I have retrieved in the last couple days.

p1151
Definition=Lack of 02 switches-bank 2 sensor 1
Explanation= ECM could not adjust fuel trim because of a lean or rich condition.
Probable cause= fuel pressure high low, MAF sensor dirty/defective,vacuum leak on engine, leaking fuel injector or fuel pressure regulator.

p1131
Definition= Lack of bank 1 o2 transitions-lean
Explanation= ECM detected back 1 02 at its lean limit
Probable cause= Misfire on bank 1, vacuum leak affecting bank 1 only, fuel injector problem bank 1, engine mechanical condition.

p0136
Definition= Ho2s12 circuit condition (heater oxygen sensor bank 1 sensor 2)
Explanation= The power-train control module uses the oxygen sensor to calculate the air/fuel ratio in the exhaust.
Probable cause= oxygen sensor defective, fuel system running very rich or lean-check other codes first, engine misfire condition-repair, fuel pressure very high or low- fuel pump or pressure regulator.

p2270
Definition= Lack of heated oxygen sensor - bank 1 sensor 2(ho2s12) switches- sensor indicates lean
Explanation= ECM forces the fuel system rich and lean- test fails when sensor does not react as expected.
Probable cause= failed oxygen sensor, air leak near oxygen sensor, poor electrical connection in sensor circuit.

p2271
Definition= Lack of heated oxygen sensor - bank 1 sensor 2 (ho2s12) switches-sensor indicates rich.
Explanation= ECM forces the fuel system rich and lean- test fails when sensor does not react as expected.
Probable cause= failed oxygen sensor, air leak near oxygen sensor, poor electrical connection in sensor circuit.

p0460
Definition= Fuel level sending unit condition
Explanation= Poor electrical connection at the fuel level sending unit.
Probable cause= Failed fuel level sending unit.

p0300
Definition= Cylinder misfire detected - random cylinders
Explanation= The power-train control module monitors the crankshaft speed and has detected a misfire condition.
Probable cause= Ignition system fault-spark plugs, ignition wires, coil, vacuum leak, injector fault, high low fuel pressure.

I'm so tired of throwing parts at this problem. I took it to a shop and they said that they thought it was a faulty spring in the engine(engine mechanical). I didn't have them fix it cause they seemed very uncertain/unexperienced about the problem. I had to move about 300 miles away and the truck barely made it. About halfway it started making a clanking sound and tried to die constantly. It barely runs now, can't get it to run over 50 mph for the most part, loss of power, misfires constantly. please please please any help greatly appreciated.

Ray

 

As a start, have you had a chance to check all the fuses? If the o2 sensor heater circuits aren't working some of those codes will come up.

 

There are some things to check out here. First off, ignore the P0136, 2270 and 2271 as these aren't a 'real' driveabiltily problem. Yes, they are codes and will set a code, but won't affect driveabiltiy.
You really should have access to a scanner to monitor the o2 sensors; they should be switching predictably once the engine enters closed loop, which will be within 2 min. of engine start, and less if it's warm.
Once started and running, monitor the o2's (both the primary ones, or, o2s11 and o2s21). The codes P1131 and p1151 are global codes for the particular banks noted. Your defintitions are a little too broad, so here's what they really mean: the o2 sensor on the affected bank was stuck below .45V for longer then 15 seconds (an eternity to a fuel system) when it was being driven rich and expecting to see a higher voltage.
That being typed, The first place to start is to look for vacuum leaks. These had a bunch of rubber connectors that liked to rot out and they were hard to find. One is directly underneath the throttle body, and connects the pcv line to the intake. Check this one carefully, as they can leak on the back side underneath and are very hard to find. You could also try spraying carb cleaner or brake cleaner around the top of the engine while looking at the o2's to see if they stick rich. If they do, there's your leak.
The other thing that comes to mind is to disconnect the EGR vacuum line from the valve, plug it and road test it. If the misfire goes away, then remove the upper air plenumn and clean out the EGR ports, as the flow from the ports is uneven and causing the misfire. It was really common for these to get all junked up with sludge and grime.
Let us know if you need any other help.

 

One other thought. The p0460 is a open or shorted fuel level sensor (probably noticed the gauge is screwed up), and the other codes (p0136) is a heater circut that has a problem. Most likely the cat. effienecy monitor is bad.