My '04 Lariat 4x4 5.4L SCAB w/ 167k miles is giving me problems primarily while in O/D around 50-70 mph. When I lightly lean into the throttle either to slightly increase speed or maintain speed while going up an incline I get some jolting coming from the tranny. It's not a one time jolt when it downshifts but a repetitive jolt while staying in the same gear. It doesn't happen until the engine is up to normal operating temperature and happens almost exclusively when O/D is engaged. It's thrown a code which I'm going to have pulled today while at lunch (will follow up with the code once I know what it is). When the check engine light has come on I can push the O/D button to go into 3rd gear and it will still shimmy the truck a bit but when I go back into O/D it seems to calm down. I'm thinking it's s sensor and I'm aware there are a few that talk to the tranny. Was wondering if anyone else has seen this problem or if someone knows what could be causing it. It started late last summer but has progressively gotten worse. It's a daily occurrence and road conditions and outside temp don't appear to make it worse or better. One more thing to note is that the jolting is significantly worse when in 4x4 high which makes sense since it's affecting both the front and rear axles assuming it's coming from the tranny. Thanks everyone for your thoughts if you can help.

 

Took the truck to a couple auto parts places and they couldn't find a code with their OBD-II scanners. So I'm stuck with going off symptoms only. Best I have at this point.

While I was out I tried to duplicate the problem in different gears at the same rev range (1500 - 2000 rpm's) and couldn't make it jolt. So it appears it only happens in O/D. It could be the engine I suppose but being that it's not across the board in all gears at the same engine speed I can't help but think it's a transmission issue. Looking at the different sensors maybe the transmission speed sensor (p/n 7H103).

Again, any input anyone has would be a huge help at this point. Thanks.

 

My 2006 5.4 4x4 does the same thing when its cold. It will shift to o/d then when you give it a little gas just to increase the speed a little it hesitates kind jolts you back and forth. If it down shifts all is well. I honestly just assume its some sort of a miss while under load. My truck has 102K miles on it and probably has the original plugs and COP's. I just assumed ,when I get around to changing the plugs, this problem would go away. If it is a transmission problem, I don't think the scanners at the auto parts store will read transmission codes. I'm pretty sure only high end scanners or the Ford dealer can see those.

 

It sounds like you have a COP issue and if so it will only get worse. Ford is a little slow about setting codes but it definitely should set one. The trouble with finding this issue without a code is that it will only occur while under load. If it is really bothering you, you could just replace one coil with a new one and drive it for a while to see if it had any effect. If not move the new coil to a different cylinder and put the original back on that one. Continue until you have been through all 8 positions. Drawbacks with this as you can see are the time it would take to get to the bottom of it, if it is more than one coil it would take forever, or it may not even be the coil. Another alternative would be to have someone who has proper equipment to check it while on the road. I rally don't know that much about mode 6 yet as i have never really had to go there but my understanding is you can do this in mode six and actually watch the misfires. My personal truck was doing the same thing and it did set misfire codes for random misfires as well as specific cylinder misfires. I first replaced 3 coils and made a huge difference but in another couple of months it started again so i just replaced the rest of them, BINGO! No problems for about 8 months then it started again. Now the only codes I could get were for lean conditions. Did a fuel rail pressure test and found the FRPT sensor sticking. Replaced the sensor and cured about 50% of the problem. I had a full set of injectors I had previously purchased for another customer who backed out on the repair so I went ahead and put them in. My truck had about 265,000 at this point and when I finished it ran like new. Hope this helps, I have seen these same symptoms many times and most people to assume it is a transmission problem, but so far in every instance I have run across it has been a misfire, usually COPs.

 

Pulled the code finally and got P0174 which basically says "something's wrong" so I ordered a coil and will start chasing the problem this weekend.

Anyone have voltage information on what the coils should read if they're good?

 

I picked up my single coil yesterday to attempt finding a bad COP over the weekend (assuming it's just one) but based on the P0174 error code what else should I be looking for? I'm thinking the MAF would be pretty easy. Also, what kind of tests can I run with a volt meter or other typical tools on both the COP's and MAF? If I can reduce my time replacing the COP's one at a time, taking a test run, and trying the next I'd really like to know.

 

P0174 is for a lean condition on bank 2. This could be caused by a myriad of things. One way you can try to isolate the cop that is bad is by ohming out the windings of the new coil and compare them to the old ones. If you have one that is really out in left field then start there. This lean condition code can also be caused by a bad O2 sensor, bad injector, vacuum leak etc. I would highly recommend that in this instance unless you have access to a modis that you subscribe to alldatadiy.com or mitchellonline. Both of these have a wealth of information and will lead you step by step through the troubleshooting process. There is a nominal fee but you only pay once annually. I believe it is about $19.95 or something like that. Significantly less than you would pay for the paper manuals at the parts houses and hundreds of times the information. You can't beat it. I would stick with looking at bank 2 to narrow it down since you do have a code for that side. Let me know if I can be of further help. I am at work right now and just don't have the time to get too involved at the moment. Good luck!

 

Appreciate the feedback but I should have posted this Saturday after I actually fixed the problem ... for free!! Pardon my ignorance with using proper names here, but the vacuum line that attaches to the PCV on the driver's side valve cover was firmly attached to the PCV but the other end of that hose was just setting on the stem and not actually clipped on. So the vacuum at the PCV was extremely hit and miss. I'm still getting a very slight jolt under the same conditions but nothing like what it was. I'm going to continue to look as there might be some lube needed on the slip yoke. But I'm mark this up in the win column for now.

Thanks everyone for your advice. Was a huge help.