powerranger262

I would definitely clean your throttle body and MAF. Is it doing it mostly when it's wet or snowing out? My truck has been going into limp mode whenever it snows, and according to my research, and the code it threw, it sounds like my intake is sucking up snow, and it's passing through k&n drop in filter and hitting the MAF wire, sending the code once it gets bad enough. It starts bucking a few times before it goes into limp mode, and then throwing the code PO61B.
I just found this info today, so the next decent day I get, I will be cleaning the throttle body and MAF, and ditching the K&N.
Wouldn't hurt for you to try. It's cheap, and it's a maintenance item that needs to be done anyways.

GigaFish

Dang I'm sorry torque isn't available for iphone, that's frustrating. If you decide to use Torque, when you download it you will need to add the Ford PID codes, which is done within the app, so no external programs to mess with. Since it isn't triggering a CEL, while you're driving, go to the "test results" tab of the app and let it refresh a few times. Try to get the truck to misfire. Then read through the tests until you get to the misfire section and it'll have a count by each cylinder! Hopefully the normal ones will be zero and the problem one will have a number!

paintballdude05

I just got home an hour ago, the truck is now misfiring while under load and idling (transmission in drive, defrost/AC on, HVAC blower motor on high). I let the truck idle when I got home in the driveway without any load and it idled a bit rough. I checked for codes and nothing came up. The fuel pressure is right around 40 psi constantly. Here is a screenshot of some of the more pertinent information that I pulled after idling for a bit. The one thing that stands out to me is the discrepancy in average readings for the 1st sensors in each bank. They're off by 0.55% while the second sensors are identical.



Yeah it was actually pretty snowy for the last two nights. That could be it too, with nearly 200k miles on it it's probably dirty. I also doubt that it's been. I wish I had the space and time to do that before my trip tomorrow.

I think I'm going to give this a try with my GF's phone. I want to get this figured out before my trip tomorrow and this is probably the easiest/ quickest way to do it.

paintballdude05

I went for another drive tonight after downloading Torque. The truck seemed to run fine and I could not get it to misfire. The Torque app didn't report anything strange either. I put about half a bottle of Seafoam in the intake, the other half went in the fuel. I'll see if that makes a difference. I'm still heading on this trip, but I'm bringing the two spare coils and some tools just in case.

The one last thing that worries me though is the possibility that there's something going on with the timing chain system. Since the truck has such high miles, I have a feeling I'm due for some TLC on that part of the engine. The truck does have that slight diesel sound and a bit of a tick at idle but it's always been like that. Hopeully this issue has nothing to do with that though.

GigaFish

Always how it works, isn't it! Right when you are all set up to diagnose it, everything works perfectly. Hope you have a safe trip with no issues! If worst comes to absolute worst I'd much rather be changing a coil at a truckstop than some other alternatives!

techrep

iTrader: (1)

I would take a spare FPDM too...

paintballdude05

I drove to work this morning, it misfired slightly going up a hill, not as bad as it was before though. The trucks idle still sounds a bit off compared to what I'm use too. It was really snowy this morning with icy roads, cars were moving like snails so I didn't really try accelerating hard to see how the truck felt.

Yes it's a PIA! I'm going to play with Torque a bit to see what other information I can grab. I might not of even had the misfire PID or w/e it's called properly activated.

Would a bad FPDM cause a spark issue? I have a feeling that's what it is since the monitored fuel pressure was fairly good. Either way I think I will order up a spare from RockAuto since I can only imagine how expensive they will be locally if/when it goes.

Martian

You should probably replace your O2 sensors.

powerranger262

I didn't see that when I first read it. Yep, pretty good chance your o2 sensors could be messed up, hopefully it didn't F up your cats.

paintballdude05

Well my trip went well, right around 600 miles round trip. The truck did misfire, but it was only at certain speeds and RPMs. Today though was a different story, the truck really doesn't like the colder temperatures. Even at idle and under load it will misfire. I'm trying to get the Torque Pro App to register misfires. I'm getting a total misfire count, 8 in a 15 mile trip. But I can't get it to tell me exactly what cylinder is misfiring. I've got something new to try but it's a pain always borrowing my GF's phone to try it out. I might just go pickup an Android phone tomorrow. If I can't get Torque to tell me what cylinder is misfiring, I'm going to start changing the coils out in pairs until the problem goes away.

As far as O2 sensors go, yes they probably need to be replaced. But it's a fair amount of money and quite the PIA to change in the middle of winter. If I can hold off until the spring I'll replace them then.