Missing, but not really (ugh)

[goatsauce]

2011 XLT 5.0 Coyote. There is without a doubt a problem, but three dealers don't seem to want to take my money.

Truck has a performance problem - it's missing almost unnoticeably at idle, but it's obvious (if you care to notice) when you hold the throttle barely open. Idle seems smooth, but if I hold it at about 1500 rpms, it most clearly and definitely is missing.

However, since there are "no codes" and since mode $06 (or equivalent for this year) shows "no misfires", none of the young folks at the dealers seem to think anything is wrong.

This really manifests itself when I'm towing a 6k pound trailer and the truck can't pull it up a 2% grade unless I drop it into 3rd gear.

Of course, if I drive it like a race car it's a beast. But I can't leave rubber at every red light, especially when towing.

Fuel trims look fine (ST bounces between -4 to +4, LT sits right at +0.5). Cleaned the TB. Cleaned the MAF. Brand new Motorcraft plugs gapped at .045. CHT sensors read 205 on one bank and 198 on the other. Coolant sensor seems find. Haven't done a voltage test, but TPS data in the OBD seems smooth.

No idea how to test the coil packs (neither does Ford). They want me to drop the $$ to replace all 8, but I'm not throwing that much $$ at a problem unless I can see real evidence a coil pack is bad.

I'm no novice however I'm losing my mind that "everything is normal" yet the truck so clearly has a problem.

This has been going on for months and I'm at my wits end. Fresh ideas, anyone?

 

[Fellro]

It can be as simple as a bad connection somewhere. Not familiar with the setup, but if there is a little "plug wire" that goes between the coil and the plug, you can get those bad as well. Most coils are resistance tested, but since it is intermittent, that may not show up. It could be as simple as a part throttle vacuum leak as well. Since it is a part throttle consistent thing, I would look for vacuum leak maybe idle air control/egr issues. Maybe even pcv, though not as likely. Could also maybe be a problem with the TPS at that point in the movement

Gotta love the no code = no problem train of thought. Codes only mean certain parameters have been exceeded. Still have a motor under that electronic control, and hard parts don't throw codes.

 

[CowboyBilly9Mile]

........This really manifests itself when I'm towing a 6k pound trailer and the truck can't pull it up a 2% grade unless I drop it into 3rd gear............ Fresh ideas, anyone?

This sounds like a great time to use FORScan and look at select/relevant PID data and the fuel trims. Also, with the Torque Pro app there are some extended PID's for Ford in there. Misfires was on the extended list and it was *something* along the lines of misfires per 1000 revs and on a per cyl basis (I didn't use this data, just noticed it was available, you'd have to go check it out). Torque Pro and FORScan lite are on Android for ~$5 and FORScan full version for windoze is free. Both have forums for supporting the usage of the apps. A few things to think about.

 

[Old_Paint]

On one that old, it could well be a stretched timing belt(s). I have a '92 that runs perfectly under any condition other than light load. Pretty sure it needs a new timing chain at 180K miles. Got a light sputter at idle, and if I put a timing light on it, the timing's all over the place unless I remove the SPOUT wire. I know it isn't nearly as sophisticated as the newer stuff (I have a 2014, too), but anything with a little mechanical wear is going to start fighting with software. With variable valve timing, these things are BEASTS, but I can't imagine them working as well if something isn't quite right mechanically. If you've hit 100K on it, and haven't swapped the timing belts on it, that might be a consideration. No idea how hard it is to do, nor how much it costs to get someone else to do it, nor even if there's a way to check them without disassembly. Just taking a swing at the pitch.

 

[Ludachris]

On one that old, it could well be a stretched timing belt(s). I have a '92 that runs perfectly under any condition other than light load. Pretty sure it needs a new timing chain at 180K miles. Got a light sputter at idle, and if I put a timing light on it, the timing's all over the place unless I remove the SPOUT wire. I know it isn't nearly as sophisticated as the newer stuff (I have a 2014, too), but anything with a little mechanical wear is going to start fighting with software. With variable valve timing, these things are BEASTS, but I can't imagine them working as well if something isn't quite right mechanically. If you've hit 100K on it, and haven't swapped the timing belts on it, that might be a consideration. No idea how hard it is to do, nor how much it costs to get someone else to do it, nor even if there's a way to check them without disassembly. Just taking a swing at the pitch.

This is a really old thread Tim, but appreciate you trying to help the guy. At the very least, anyone coming in with a similar issue could benefit from your response even if the original author probably won't.

 

[Old_Paint]

This is a really old thread Tim, but appreciate you trying to help the guy. At the very least, anyone coming in with a similar issue could benefit from your response even if the original author probably won't.

Oops. Guess I've been gone too long. Showed up as a new post for me, LOL.

 

[Old_Paint]

This is a really old thread Tim, but appreciate you trying to help the guy. At the very least, anyone coming in with a similar issue could benefit from your response even if the original author probably won't.

BTW, I just looked at the bump-side photos. Good lookin old bump. I got my DL in a "new" '73 that was a teal blue. 302 with 3 on the tree. Geared like a tractor and would pull the gates off Hell.