2002 f150 7700 with 5.4 liter and 4r100 tranny. was fine yesterday now it wont even run in drive, started chugging under acceleration and now this... reverse works perfectly i can lay a strip down the road... wondering if its a torque converter issue? maybe the vent is blocked for the tranny? it's been in the mud many times

 

I had same problem. I spent 500 on motor trying to figure stuff out. Truck never threw any codes. Finally after three months it ended up being bad spark plug.

 

its just hard to imagine a spark plug or coil causing this in drive but not reverse?

 

Shouldn't be the convertor. If it works in reverse, it would work in drive. It must be electronic, either the solenoid pack in the transmission, neutral switch (? able), or losing vacuum in drive. A load is a load, no matter if its forward or backward, so it has to be transmission related somehow. Very confusing. No codes?? Should set a trans code if it is solenoid related.

 

oops yeah i had some codes...
p0133
p0135
p0320
p1131

truck wont even start today, i'm considering changing all coil packs and plugs to brand new and changing the fuel filter and crank position sensor. if it still doesn't work from there i'm not sure what to do

 

Ok. That helps. The P0320 code could be a bad VSS sensor on the transmission which would make it go good in reverse but not in drive. It is at the back of the transmission. You didn't say, 2wd or 4wd. The 2wd is at the very tail on the drivers side. Make sure it is plugged in or the wires are hooked up. If they are, replace the VSS. The P13_ codes are the O2 sensors ( being it is at least 2, check the G200 ground for good signal) and the P1131 is also 02, so I would guess the DPFE switch is bad but could still be a grounding problem. Check those, and hopefully you will get up and going again.

Not starting today? Do you have spark? Is your fuel pump priming when you turn on the key? You can see if you have fuel pressure by locating the fuel pressure valve on the fuel rail and see if you have pressure . If yes, check the crank sensor and make sure it is clean of any crap and in good shape. Cam sensor also could do this. Can you see if any other codes set since you did your other check. Maybe that will pop up and show us what your problem is.

 

If you go to try starting it again, hold the pedal at the floor and let it go thru the clean out cycle and see if it will try and fire then.

 

I had issues very recent with my 2000 5.4 not wanting to start but every once and awhile if I floored it while cranking it would sputter and start. My problem was actually a bad IAC valve it had a dead solenoid and therefore wouldn't tell the truck how much air it was pulling causing it to foul the plugs which is why pushing the pedal down helped starting the clean cycle. The IAC is responsible for how much gas to air ratio you get while starting and at idle which could also cause your problem with shifting gears and stalling out. It's a cheap fix and takes just a minute to do. Otherwise I'd do a fuel leak down test to make sure you are keeping pressure while hot and while cold. (Should stay pretty close to the same)

 

it is a 4x4 7700 model with the 4r100 transmission. i've changed the cam position sensor and IAC and i beleive DPFE is only on 2004+ models cause i cut the spare tire off and i didn't find one there. Could those transmission speed sensors cause a no start situation?

 

No I don't believe so. Have you done a leak down test yet?