Hello fellow Ford enthusiasts,

I recently (1 year ago) inherited a 2005 F150 from my late father. It runs fine but is a dog. It's very slow. When I'm getting on the on-ramp I can mat the pedal and it will downshift to 3rd or second but not feel like it's getting any faster. I've not ridden in another 5.4 from this era so it could be how it is or there could be issues

The engine was replaced a couple years ago, pulled from a used truck with under 100k. Transmission has been rebuilt, seems to shift fine. Those two things were before I got it. Body has 275k miles.

​​​​​It has an edge tuner but the screen is messed up so I've just disconnected it and left it off. I've only changed the oil and air filter since getting it. Paperwork for the motor change shows they did motorcraft plugs at the same time, so the plugs have about 10k miles on them.

I recently replaced a couple coil packs because the area where they connect with the wire harness was broken off. They were still connected and truck ran fine but I wanted to be safe. Replaced with genuine motorcraft COPs. I forgot to connect one of the cops and when I started the truck, it missed something awful. No check engine light came on. I shut it off and reconnected the plug and it ran fine again. Plugged in my scanner and no DTC's were logged. Odd....

Anyway months later, I still think about how gutless this thing is and decide to check fuel trims. Plug in my scan tool and HEGO B2S2 is reading no movement. All other sensors are running. Sensor must be bad. I've got a new one I'm putting in tonight but I'm worried that the truck seems to be ignoring faults.

Anyone have any insights? I'm thinking the edge tuner might have messed something up. I'm contemplating having Ford re-flash the PCM so that I can have a good baseline to start figuring out why it seems like a dog. Any thoughts on that? Any estimate on cost?

It seems to run smooth most the time and has no trouble holding 70mph all day long but sure takes it's time to get there. Sometimes it feels dangerous when trying to merge. Every now and then if I start it (even though engine is at temp) and get on it to get up to speed, it seems to ping until I back off the throttle. An example is getting gas then merging back into the freeway. Won't do it again the entire session no matter what hill you pull. I wonder if the detonation is causing timing to be pulled and then translates into slow acceleration?

I'm a mechanical engineer and no stranger to wrenching so If you have technical insight you want to dump on me I'm all for it. Thanks for any insights!

 

my next step would be check exhaust back pressure both pre and post cat

what are your short and long term fuel trims

 

How bad is screen on edge?, were you able to “return it to stick” before removing it? If you can’t, but want to try it, I could check required key strokes on mine so you could try to do that “blind”.

I’m a big fan of edges, but suppose it’s possible someone did some wild/significant “custom settings” with it.

absent any better intel from others, I would try to do some other basic tune up stuff: new boots/springs, checking torque on plugs at same time (and maybe pull /check a couple while doing that), clean MAF, remove and clean TB, then a throttle relearn.

Are you running stock tires/wheels/suspension ?

 

B2s2 oxygen sensor is for monitoring emissions only and has nothing to do with the performance of the engine or how it runs.
The upstream sensors are what matter, but the truck also has to be warmed up enough to be in closed loop mode before they mean anything.

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I'll check back pressure tonight and report back. Since I'm replacing the O2 and will disconnect the battery, I'll report the fuel trims after a couple days of allowing the computer to relearn. Thanks for the suggestion, I've wondered about cats as they have 270k on them as far as I know, they might be getting plugged.

 

The screen is all black when it's powered on. I tried paying with the dimmer setting but didn't make a difference. If you unplug it for a long time then plug it back in, you can see stuff for a bit but then it goes all black. I'm not familiar with edge at all, so I don't know what tune is currently in effect but it seems to be preventing DTC's from registering at all.

Tires and suspension are stock. Those other items you pointed out I'll look into, thanks!

 

The upstream sensors appear to work, they were reading similarly. So the downstream have no effect at tuning or trimming of fuel? Just there to set-off a code when cat efficiency falls below a threshold? I guess I was most alarmed that the sensor wasn't functioning at all yet no codes were thrown by the computer.

It has me wondering if there might be more wrong with the motor, like a sensor out, that could be contributing to what I perceive as lack of performance but a code isn't being set. I ran it without a coil pack plugged in and it didn't even bother to set off a code for that, all other vehicles I've worked on before would have immediately set off a code. Maybe this thing is different?

 

correct, the downstream are used for monitoring catalyst efficiency. The pcm looks at the switching ratio of the upstream sensors vs the downstream and will throw a code if the frequency of the downstream switching is greater than something like 60% of the upstream. The downstream actually should be a fairly flat line if the cats are warmed up and efficient, but probably not a perfect flat line.

As for the codes, or lack therof. Yes if you unplugged a coil with the truck running it should throw a code for that. Does your code reader appear to be doing what it should when plugged into the truck? my suspicion would be that perhaps one of the wires/pins on the obd port has a problem which is not passing the signal to the code reader. Could potentially also explain the problem with the edge tuner. I am curious what would happen if you were to plug the edge into a different vehicles obd2 port just to see if the screen powers on?

 

Make sure your fuse #41 isnt blown, I believe it should power the obd2 port.

 

The scanner powers on and appear to read all of the live data correctly. It reports no pending or set codes and that the truck is emissions ready. I have two other scan tools I can try to confirm functionality, I hadn't thought of that. I'll also check that fuse

I don't own another obdII car but have friends. I can try plugging the edge into to verify its behavior, thanks for the idea!