jeremys88

f150 fans, experts, enthusiasts, thank you for taking a brief moment to read about my problem, I know it is kind of lengthy. Also, this is my first post on this forum, so I apologize for any redundant statements:

I own a 2WD 2006 5.4L v8 f150, 108k miles when I bought it, 120k now. I bought the truck used 14 months ago (Jan 2011) and within a few months of owning the truck, I noticed progressive slipping. It slips as soon as I press the gas from sitting idle with my foot on the brake (unless I just let off the brake and let it roll about 10-15 feet and then BARELY accelerate), And also experience violent slipping from between the range of 45-55mph (but usually, I can avoid slipping if I just barellllyyy accelerate from 40 mph to 55mph range)
About a month ago I mentioned the problem to my brother (some experience with vehicles) and he said fords are notorious for shuddering, and that I needed to replace filter and 5 quarts of fluid. So I had him replace the trans filter and put 5 quarts of mercon v and a quart of anti slip trans fluid in. The plug was in the pan so I'm assuming the transmission fluid hadn't been replaced before that.
I can tell you that immediately after he replaced the filter, it felt 90% better for about the next 50 miles of driving. I hardly noticed any slipping/shuddering off the line, and again, hardly anything from 44-55mph range. Although, now I'm beginning to think I was just imagining that it got better.
Regardless, it is now as bad if not worse as it was before the filter replacement. I've read a few posts from other gents who said that it ended up being their COP (this is an ignition coil?) and to take it to autozone for their diagnostic test. Took it in to AZ, but because I had no check engine light, they could not pull up any codes and also said if there was misfiring the check engine light would have come on.
SO NOW I AM STUCK. I have no idea what could be the problem, and I don't have a lot of money to throw around trying to play process of elimination and I am hesitant to take it to a dealer and be ripped off.
Can someone PLEASE provide me with any insight?

JimWills

Probably a dumb question but I noticed you said 5 quarts instead of filled it back up. I assume you checked it with the dip stick.(hot with the engine running). Also a lot of people get the fluid exchange or flush where they swap the fluid through the lines to the radiator. if that had been done the plug would still be in the pan. (mines never been off)
another thing to try is reset the ECM by removing the Battery cable for 15 min. I know someone with an older 96 Taurus that wouldn't go into overdrive and that fixed it.

jeremys88

Jim- Thanks for the reply. Fluid level is normal.. I'm going to first replace all spark plugs, and if that doesn't help I'll take it into the dealership to see if a coil is bunk.

kdcntn

Had the exact same problem with my '97, 5.4L Triton. Changed all the COP's and the problem (probably mental) changed for about a day. Now it's back.
Did your truck make a grumbling noise and change somewhat if you let off the gas?

I am still convinced that it is the plugs, but I just changed them a year ago. I'm now wondering if I have a bad plug.

After awhile, the light on the end of my shifter will flash, which I've been told is a transmission slip. But it doesn't do it for quit a while and goes off immediately after I turn the truck off and then back on.

One thing I DID NOT do was to unplug the battery cable. Will try that today. Thanks for reminding me, JimWillis

Prof

Wait wait...when you say "slipping" did you mean that the wheels (on one side or the other) seemed to stutter, meaning that it felt like a peel out on one side or the other maybe when you were turning right or left?

If the problem was a coil or plug - first, when they fail completely, you truck will turn to a limping turd, it will be horrific, not just a stutter (in my experience) - now you may be experiencing misfire, but that to me, at speed felt like a surging and dropping off of engine power, almost like you are at the end of a tank of gas and the feeling is something akin to the last drops of gas hitting the engine, and the things surges and then lays back. You will be able to see misfires on an OBD program as they happen (but before the engine light goes off - as the engines apparently are designed for a certain amount of acceptable misfires before light goes off)... I have the $23 OBDII dongle from Amazon and the 5$ Torque Pro program for my Android phone, and it has paid for itself ten times over - hell Ford charged me $100 bucks just to put my truck on their diagnostic machine, when it was a simple misfire code...

With the transmission "slipping", does the engine rev higher when it slips? In other words, does the truck downshift into a higher RPM, or is the shifting erratic when going up hills and things like that? On a pan drop for my 2005 5.4 (now done twice), six quarts of fluid is about right, I think manual says seven and Ford does 6 1/2, which keeps the fluid level on the low but acceptable side - my pan drops were done within the last month (most recent two days ago so I could put in a pan with a drain plug), and mine hadn't been touched for 92k miles (so pretty close to yours) and it smoothed out things, but there was no real remarkable changes, except the strange shifting on hills seems to have stopped.

NOW, Saturday, I changed out my rear differential fluid - I am sure the first time this was done too...put in clean fluid (amsoil extreme gear 75/140) and fresh Ford friction modifier because my rear end had been chattering when I would take off from a stop while turning right - it was like a peel out kind of...when I wasn't really stepping on gas heavily -

First drive with new fluid was this morning, so the gasket could cure, and BROTHER, let me tell you - it has smoothed down my ride completely, across the board - I have been feeling a vibration at speed that comes and goes, and I narrowed it to the emergency brakes catching and the rear diff (having changed everything else) and while I am still getting a slight vibration, it calmed down completely and my whole truck is much smoother going down the highway...the brakes still need attention, but it is not so dire now I think...I will keep checking it out.

BUT before you spend wads of cash with dealership diagnostics, you can do a little of this yourself - I had one COP go out and the dealer locally charged me 400 buck plus to change it and the plug in the No. 4 cylinder (not easy, but certainly not $400 bucks worth - as I had already changed the infamous plugs to brand new not two months ago)...

Good luck...gremlins in the Ford suck don't they?

kdcntn

Prof, I'm Not Sure If You're Talking To Me Or The Original Poster.
My Truck "Slips" While Driving OnThe Road Not AT Takeoff.