I have a 2008 F150 4x4, 5.4. 105000 miles.
1)The main issue I'm dealing with currently is a loss of power. Under normal driving conditions it does ok. I feel like there should be more acceleration but I can't say that for sure. However, last week, I volunteered to help pass out some supplies to some folks that were in need. They loaded my truck with cases of water and food. It was definitely loaded down but nothing super crazy. It seemed to do just fine until I tried to drive up hills, while going up I would completely lose power. Pedal to the metal and barely moving. Scary situation. If took the hill with a bit of a start, it accelerated through but did not feel right, way too much acceleration needed for the situation. This happened throughout the day even after unloading a vast majority of the supplies. I've had issues with spark plugs and coil packs in the past but got that all sorted. It's not throwing any codes. It has shifted a bit hard a few times in the past but fluid level seems fine. Maybe even a bit high. (I'm thinking the last shop I took it too "topped it off" and added too much)
2) the second less serious situation is the 4x4. When I put it in high or low, the 4x4 indicator light comes on for a second and then goes off. However it is definitely still engaged. If I turn the wheels excessively, they skip until I take it out of 4x4. What's going on there?

Any advice, help, or insight would be greatly appreciated.

 

The first issue definitely sounds like a COP/plug issue. When you replaced the COP's did you use Motorcraft parts to replace, or did you use a store brand/off-brand? Also, did you use the proper Motorcraft plugs (SP546)? Issues with other brands, even Champions or NGK's, have been well documented. As for the COP's, if you don't want to spring for the MC's then go with a well known brand, such as Accel or Mallory. I'm currently using Accel Streetfire COP's.

Regarding your 4x4 issue, it sounds like your switch, transfer case motor and IWE's are all working. Perhaps it's a loose connection with the indicator light?

 

The plugs are motorcraft. The COP are Accel. When I was having that issue, it threw codes and missed a lot. Since replacement, no codes no missing I can detect.
I don't THINK it's a loose connection because Everytime I put it into 4x4 the light comes on for a second.

 

Do you have an OBDII reader? If not, pick up a bluetooth unit off of Amazon (about $30) and download the Torque Pro app (Android only) for $5. It can tell you if you have any "pending" codes. It could be a transmission issue, but most of the time the symptoms you've described end up being caused by a bad COP or two.

The issue with the indicator on your 4wd selector switch is puzzling but I still say it might just be a loose or breaking connection on the light itself, if everything seems to be functioning in 4wd.

 

Missing a lot may have melted CAT and plugged it up?

 

CAT is what I was thinking......... do you have a code reader to see real time data ? Monitor temp across the CAT.

 

No unfortunately. I have a cheap reader that will show me codes it throws but that's it. After these multiple issues, I'm trying to research my best option for buying one.

 

A corroded FPDM can cause all manner of symptoms, and the truck falling on its face under load is one.

I'd at least drop the spare and see if your present unit has standoffs. If not, I'd remove it and check for corrosion on the underside of the case.

 

I ordered a Blu tooth OBD II Reader but in the mean time checked the cat temps with an infrared gun. Information it's 480 ish, behind it's 380 ish, on both. Am I interpreting this as meaning the cats are most likely good?

 

Lets see what your obd says the temp is . They really run much hotter than that . But It depends on how you are doing it . You may need a pressure check. Your readings are indicating a problem .your symptoms sure sound like they may be plugged .
Torque pro app 5$ and a cheap bluetooth reader into an android is a good one .You may try pulling o2 's out and see if she runs better to open air ,it will be noisy .

 

Ok. I finally got my reader in yesterday and downloaded torque pro. I got it all linked up and did some basic stuff but I could use a little guidance for this app. I tried looking around the site for help on setting up the app the best way but pretty much everything I find is for diesels. Can anyone point me to some set up guidance for my truck on the app or is the way it automatically is ok? I tried looking through the various menus for temps on the cats but didn't see anything.

 

You'll probably want to use one of those thermal IR temperature guns to measure catalytic converter temperatures.

 

That's what I did first and got the results of 480 in front of the cat and 380 behind the cat.

 

If the assembly is working the temperature reading from the outgoing gases should be 30 to 100 degrees higher letting you know the chemical reaction is occurring inside.

If the assembly is not working and worn out or is partially plugged the outgoing reading will be colder or the same in temp as the incoming reading.

 

To me the symptoms indicate a restricted exhaust. It is starting to sound like its the cats. Park it in a bad part of town and maybe some bonehead will steal the cats and your insurance will cover it. Just kidding....