Hello everyone,

Im new to this forum, as I have recently purchased a 99 F150 XLT 4x4 Off Road with the 5.4 in it. It has the 4R70W transmission in it with the manually shifted transfer case.

I bought the truck knowing it needed some work, but I believe I may be in over my head. I work in a transmission shop, so having a truck with transmission problems typically wouldnt be a problem. However, this truck is being quite stubborn.

Ive got/have had several different trans codes (EPC solenoid, TCC solenoid, shift solenoid A and B, and one other...) Im sorry I dont remember the code numbers right now.

I did a little research and found a TSB that had a few of the DTC's I had and it said it could be from a bad lead harness and or bulkhead connector. Ordered them both from ford, along with the shift solenoid pack. I lost 2 codes after doing that, but still have the same problem:

I can free rev without any problems, unless I give it full throttle, then it want to bog down and act like its starved for fuel. Which is almost exactly the same thing it does in gear, but you can BARELY touch the gas pedal if you want to get moving, then you are stuck in second gear/ limp mode.

I initially thought that maybe since the trans was in second gear limp mode, that was why it was bogging down, but now Im not so sure. Obviously I DO have some transmission issues, and due to the amount of corrosion that was in the bulk head connector, I plan to get a new harness side connector and pig tail. I dont know that will solve my problems though.

Ive been looking through All-Data and out Snap On verus at the trouble shooter to see if I can get any hints or tips. All the codes say that they are related to shorted wiring or a bad PCM. The wiring I know is fine, and I dont want to condemn a computer if I dont have to because they arent cheap.

I think maybe I have an EGR or something related problem with the engine, and thats why I cant give it too much throttle. I did an EGR duty test, and saw the EGR valve working, and for a while after that, I never had any issues. Some days the truck acts up when its cold and will rev fine once warm, and some days its the complete opposite.

Im just at my wits end with this truck, and just want to be able to drive it finally. If you guys/gals can give me any input or any suggestions I would appreciate it.

I apologize for the long first post, but I have been googling and searching every website I can find, and just cant figure out what to do to this thing. Im also sorry if what Im describing makes no sense, and if thats the case yell at me and I will try to explain better.

Thank you in advance.

 

So Im beginning to think that most of my problem is in the engine compartment. I checked fuel pressure today, and everything checks out. When I go wide open throttle, it barely makes it to 2k ROM, and most of the time when it does hit 2k, it completely dies and I have to crank it over to restart it. Sometimes it will hit the 2k mark and spit and sputter to 2500, then rev good for a few hundred RPM and do it all over again. Fuel pressure is a little shaky, but holds about 40-42 psi at WOT and 32 at idle.

When I first start it up, and give it gas immediately, it revs like there isnt a single problem with the truck. As soon as I let off the gas and hit it again, I starts to act up.

If anyone has experienced these problems, please let me know. I appreciate any insight and help I can get.

I also put on the new pigtail to the trans bulkhead, and seem to have taken care of most of my transmission issues.

thank you in advance.

 

Keep in mind the PCM has a rev limiter in it. Without being under load the PCM will not allow you to go much above 2500-this is normal.

 

Its not hitting the rev limiter. I can rev to 5000 RPM in park or neutral when its running smooth. Just went out at lunch time to look at data again. All my data seems to transmit properly, and no codes for anything to do with the engine. When I hold the engine RPM at 2500, it will have a slight sputter, then run fine for a few sconds, then another sputter and go back to running slightly rough again. I held it like that fo about 3 minutes and it was constant switching every few seconds like a solenoid or something was opening and closing.

By the way, I only have 4 codes out of 9 left in my transmission:
PO1747, 755, 743, 1760

 

I have been chasing a similar isse. I have finally narrowed mine down to a bad bulk head connector, and a bad fuse box. It has taken me nearly 2 months to find this. As it was not very apparent. It also took out my pcm at the same time.

 

It seems you have access to the scan data so after scanning for codes, I'd want to check the fuel trims. The long term fuel trim (LTFT) PID will tell you how the PCM is responding to the 02 sensor input. Both banks should be reasonably close and within 15% of programmed fuel delivery. Therefore if both banks are outside this range, it would suggest that your problem is common to both banks. If only one bank is outside this range, at least you've narrowed it down to that bank. It's a start.
Just a little tidbit : I went to an emissions seminar a few years ago and the instructor started the seminar by saying "I can tell the performance condition of any engine by the pattern on the o2 sensors. This is very true. A digital scope to diagnose a problem like this is of huge value-something that even a Ford service manual won't give you.

 

Fuel trims are within spec. Injector pulse width is within spec. There are no down stream converters, someone has cut them out and put a straight pipe in place. I'll get to fixing that eventually.

I put a new fuel filter on it. Fixed some vacuum lines. Put a new tps on it.

It will now rev to 5500 at partial throttle without a single problem. However, at wide open throttle it spits and sputters still. It revs like its going through gears. It's rough for a couple hundred rpm, clears up, "burps" and revs again, "burps" and does it 4 times until it reaches about 5000 rpm.

It's giving me a fit. Before I drop $300 on a new PCM, I want to make sure it's not something simple. And it seems like its going to be.

 

I am new here and encountering the same issue with my truck and was wondering if you ever figure out the issue

thanks