Hey guys, I've run out of ideas on my truck. Sorry about the long post, but want to give you all of the info.

2000 F150, 5.4, 4x4, 167,300 miles.

Here is the story. I put several (about 5) gallons of old gas in it (I know terrible idea, chastise if you must) and toped off the tank with premium (another 13 gallons). About 3 weeks later the truck started running rough and missing. I removed the gas from the tank and replaced all plugs and COPs, cleaned injectors, and replaced fuel filter.

After that i started getting P0354 and P0355 codes and a little while later started getting P1131 and P1151. I then checked and re-checked all plugs and COPS, cleaned MAF and Throttle body. Codes still there, so i replaced MAF and upstream O2 sensors. That cleaned up the P1131 and P1151 codes, and ran a little better

I then check the wire harness down by the AC accumulator, didn't see any problems there, check the connections for both #4 and #5 COP, making sure they were connected securely.

After reading many posts on this forum....

I read that the fuel pump can cause miss fires, so i replaced the pump and the screen. This made the truck start easier and run a little better, but still pretty rough. Pressure at rails was about 30 psi before pump, and 38psi after pump.

I swapped #4 COP with #1 and #5 COP with #6. No love... Then I swapped #4 Plug with #1 and #5 plug with #6, still no love. Then swapped injector #4 with #1 and #5 injector with #6, still no love.

Also did a compression test on all 8 cylinders, the news wasn't so good.
# 1 - 90 psi, #2 - 120 psi, #3 - 140 psi, #4 - 80 psi, #5 - 60 psi, #6 - 145 psi, #7 - 140 psi, #8 - 140 psi.

Knowing that the compression is bad in 3 cylinders, that would cause the rough running, but doesn't seem like it should cause the P0354 and P0355. Could it ?

Also the P0354 and P0355 only seem to happen when truck is ran around 3000 RPM. This seems to mean that it is a problem with the electrical connections or the PCM. I Did some tests, both have the + line at 12V when the ignition is on. Also when test light it hooked up it does flash correctly.

Anybody have any ideas that may help me out?

Thanks in advance.

 

Codes 354 and 355 are cylinder 4 and 5 coil primary open codes.
The harness, coil or PCM switch is in trouble. The PCM connector is also in the mix.
Switch coils to the other bank first to see what happens.
If no help, you have the harness or the PCM left.
Coil power is supplied to all the coils through a single fuse so a loss at one or more can only be the harness.
Looking back at the PCM switches through the harness should see some high resistance of 10k or higher to ground if the switch is not shorted or open.
To make it easier, cut the connector off a coil with it's coil side terninals intact and solder some leads to it and plug in the harness connector.
If this only shows at rpm then you have a more difficult time running it down without spending money on parts or better diagnostic methods and equipment.
Good luck.

 

Thanks Bluegrass, i'll try and spend some time with the harness in the next couple of weeks.

Another question...

If it were the PCM should I be having trouble with all of them? or can just a couple of outputs go out?

Being a computer engineer I'm pretty used to tracking down electrical and wiring issues, but not super excited about trying to find it in the truck harness .

 

One other question.

What did you mean by this? What parts or diagnostic equipment could help out?

Thanks

 

..First question; the COP coils are fired with seperate solid state switches so each of their timing can be altered near instantly independently.
This is in lue of the old distributor way.
..Second question; there are high end scanners that can look into the PCM program and see responses real time and even trap faults on a freeze frame basis.
..A dealer level scanner can even do program routine commands and see the results.
..The user must still interpet the results and take the actions in any event.
..The program, in this version, has never reached the level of 'pinpointing' a fault and reporting it as such.
..The 'average owner' does not know how the major sub operations work so can't relate very easy to the fault codes.
..For instance a code 174 discripts as lean bank 1. What often is missed is this refers to what the program has done and not 'directly' to the hardware.
..What it says is the program fuel table for bank 1 has been shifted to the lean end of the table trying to 'correct' for a rich condition. When an out of limit value is reached, the code and CEL lamp are logic tiggered on. This is where many go the wrong direction with code interpetation.
..All this is exactly the way a computer works except it is a specific application where the inputs and output to the computer are controlling actions in a loop fashion and with self diagnostics and pre- diagnostics tests are run as a routine function.
..With this system, it has ihe ability to self adjust the operating tables over time to account for mechanical wear as the engine ages until something falls out of program limits and is reported.
The whole operation is pretty well advanced.
If you want to look at a more indepth overview, go to the Motorcraft website and down load the whole doc for your year and model. It's about 120 pages.
Good luck.

 

Wow... this is my first post but Ive been studying everything i can find on the whole 4.2l lean codes problem. The mil on my 03 4.2l came on months ago but truck ran fine...until about 2 weeks ago. Loss of power, idles rough, etc... stored codes were IMRC bank 1 stuck closed, bank 1 system too lean, cylinders 4,5,6 misfire. Pulled intake plenum, replaced all 4 bushings on both connecting rods (pass side rod had come loose from pass side rail), isolater bolts, upper plenum gasket, plugs, wires, checked for vacuum leaks but couldnt find any. I was sure the problem would be solved... its not. Trucks been parked for two weeks and no answers in sight. I dont have the money to keep replacing parts or tow it in for a diagnosis by a real mechanic. Then I see your explanation of interprentating a lean code... is my truck trying to correct a "too rich" condition on bank 1??? I cant afford NOT to fix my truck either and could really use some help here.

 

bphelan,
list all the codes you see, then we can go over them.
Sorry you did all that work and not get results.
The codes really need to be understood first for what they point to, then a breakdown of them into possible faults.
Good luck.

 

bphelan,
Sorry to hear about your problems. For my truck the low compression ended up being a major problem. However, I did have some bad injectors on the cylinders that had low compression.

Sadly, though, I ended up going the expensive route to fix mine. Put long block in it from Ford . Ended up being over $6,000 by the time it was over with.

Hopefully you solve your problems soon.

 

Oldyella: thanks for the reply... something similar to your experience is what im really beginning to fear. I bought may truck for 7,000 in Sept. 09. It's really clean and has been running great until now. I have to much into it not to fix it right and drive it for many more years. Where the money's gonna come from remains the question... but finding and getting involved in this forum is very encouraging. Im learning alot in just a few weeks.

 

Bluegrass: codes are as follows... P1519, P0171, P1131, P1151, P0175, P030(4,5,6). I posted allot more details the other night in a thread i started about 'Testing a catalytic converter'. Looking forward to any input you have. Thanks

 

....Well you certainly have a code problem.
....Codes 171 and 1131 are a legal pair indicating bank one is lean. That's proper.
....Code 175 indicates bank 2 is rich but the 1151 say it's lean. This cannot be! They are at odds with each other.
....The 304,5,and 6 are cylinder missfires for 4,5 and 6.
Note: the 175 and 1151 codes at odds are also on bank 2 that had the missfires so some confusion has taken place if the codes are correctly read..
....Are you sure you have all the codes correct?
....I would be inclined to clear the codes if you have them listed correctly for reference and see what returns after you run the motor. This way you are not getting confused by old history but see the latest, then begin troubleshooting that new list starting with any missfires first.

 

got it! yeah, those were all the codes read from a couple different readings over the last couple of weeks. Ill do the reset and confirm the current codes. thanks

 

Trucks in the shop being diagnosed. I'll let you know on Monday evening what I find out and hopefully determine a course of action that fits my budget (or lack of one I suppose!). Thanks for all the info!

 

cats were clogged and the engine couldnt be properly diagnosed so i towed it home, pulled of the cats and did my best to ream them out. Put them back on the truck and it ran ok but I still think theres some back pressure. after about 40 miles, the mil came on again but i dont know what the codes are until i borrow my buddies scanner again and check it out.