98 Ford F-150 5.4L V-8 4x4 - 5 Codes - Ford Forums

advisual · 08-06-2008, 16:27

Hi All,

I bought this truck from a good friend that bought it new, so I know it was well cared for. I've owned it for about 8 months, for the most part trouble free.

Recently I started getting codes, mostly P0174 and P0171.

So we found the PCV elbow was bad replaced that and the hoses connected also replaced one of the coil on plugs ( COPS ) and the truck ran perfect for about a month.

Now the truck suddenly starts running bad and throws up 5 codes: P1131, P1151, P0171, P0174 and P0136.

On visual inspection it seems like the hoses are all good. But I'm wondering if one of the other COPS have gone bad.

The truck has 160,000 miles and will drive pretty good at speed. It stumbles when I roll to a stop at a light but will not usually turn off. It feels like it did before when the vacuum line was the problem.

Any ideas or suggestions would be greatly appreciated.

kaboom10 · 08-13-2008, 18:50

Sounds like a possible COP going bad from what you discribe. They can go bad without throwing a code also. The ECU needs to be tested to reveal what's going on. I have only heard the dealer has the equipment to read the ECU unless a repair facility has one but it's rare. All the codes are lean codes with the exception of the last one which I don't know. The code read outs say the 02 on each bank is bad but the odds are high that both would be bad.Try intake leaks in the manifold gasket for the intake. Spray some carb cleaner in and see what you get. Clean the MAF sensor with cleaner made for it.

ymeski56 · 09-09-2008, 20:18

Does it run ok til it warms up, or run bad as soon as it starts? What Octane fuel did your friend used to use? Do you use the same, or different? How many miles on the O2 sensors? When changed, were they changed one at a time, in pairs or each side or all at once? In the mean time, p/u a can of Electronic Contact Cleaner (rated safe for plastics), check Voltage at each o2 sens's connector & see what you get for each signal wire to ground & heat wire to ground. Personally, as long as I was down there, I'de take out aech sensor & douch the probe head w/ the contact cleaner & reinstall. I'm also leaning towards a Vac or rouge source air passage. EGR's can serve up a 2xwammy by developing pinhole leaks of its Vac actuator diaphragm. Causing Idle instability & a slowed and limited response with trim adjustments when demanded by ECC in response to lean/rich signals given by O2 sensors. EGR valves also req. port & valve seat cleaning occasionally.