Hi, I recently started experiencing a power loss on my 2012 5.0 with 153,000. Under acceleration the tac and the speedometer both stop moving around the 3000-4000 range. When I let my foot off the gas a little it starts to accel again and is fine. It kinda sounds like its bogging down in that range. Doesn't do it in first gear, more so in second and up. No starting, idle or cruising issues. I have a k&N cold air intake, throttle body spacer, Kamikaze exhaust and 87 performance tune from 5 Star tuning. No check engine light. Cleaned the MAF, airfilter, throttle body and put in new spark plugs. Anyone got any ideas on what the problem might be? It seems like a fuel issue to me but looking for a second opinion. Thanks in advance!

 

First thing you need to do is take the throttle body spacer off and sell it. It bought you nothing but a lighter wallet and quite possibly the problem. While you're at it, you can do the same with the K&N crap. It bought you nothing. The stock unit provides all of the cold air the engine needs. Trust Ford, if there was any fuel mileage or performance increases to be had, it would have come on the truck. The exhaust bought you noise and reduced the low end on it but can provide a few ponies at WOT. The issue you are having sounds like a plugged converter and at your mileage is a real possibility. I would suggest buying a cheap laser probe at Harbor Freight and see what the temp is of the converters after a 30 minute run. It should not go over 400C. Or you can check with any of the exhaust shops, they sometimes do a check for free hoping to get work from you. With your setup. I'd suggest getting a high flow unit if it needs replacing.

 

Just to elaborate on what Labnerd said, the TB spacer does nothing, back in the days of carburetors they actually helped by adding in turbulence to aid in fuel atomization, but with port fuel injection there is only air at that point in the intake tract, so the turbulence they add is not needed and may actually hurt performance. Turbulence actually slows or reduces flow to some degree.

Now for the cold air intake from K&N, the factory intake tube and mass air meter flows "X" amount of air for a given throttle position and the stock tune knows what that is and sends the correct amount of fuel to the engine. When you put on a CAI that does not require a custom tune (like the k&n) it basically flows the same as stock so guess what that means it makes no more power than stock. It may look better than stock or even sound better but that's all it does. If you want a CAI that actually does make power then get one that requires a custom tune because they actually flow more air than the stock tune can adjust for so when you get a tune for them they make more power.

 

Hot air intake and throttle body spacers suck X3.

The aftermarket intakes are really only for noise unless you have done a lot to your engine i.e. port and polish the heads, port matching the gaskets, bigger cams etc. The factory tubing provides all the air the engine can use while keeping noise and water away. Also, the MAF and throttle body have not changed in size so the two smallest cross sections in the intake tract remain the exact same. The actual airflow into the engine has not been noticable changed.

The throttle body spacers would serve you better if it was in the shape of beer cans as it does absolutely nothing for your truck.

My suggestion is to disconnect the battery then turn your headlights on. Leave them like this for a good 20-30 minutes. This will clear out the PCM and reset the shift strategy and throttle pedal sensors. While this is going on take off the TB spacer. Then reconnect the battery but make sure to turn the lights off first. This will eliminate and chance of a learned PCM setting causing the problem. Also, check if there's a way you can easily recalibrate the throttle pedal. I don't remember off the top of my head if that one can be done without the right computer connection.

If that doesn't work check the cats like mentioned above. They could be starting to fail.

 

Thank you everyone for the advice.

Wookie:

After disconnecting the battery, turning on the headlights then turning off the headlights and connecting the battery, will the 87 performance tune I have on my truck right now override the PCM, shift strategy and throttle pedal sensors with the adjustments in the tune?

 

No, the shift strategy is set by the tune and fine tuned by your driving. Everything will be set back to the base settings for the tune.

 

So yesterday I did the battery and the headlights process and the problem was still there. I ran my tank down to almost empty, put in 12 gallons of E85, bottle of Techron and switched to my E85 tune and the problem went away. When the tank of E85 is gone, I'm going to put in 87 and the 87 Performance tune and see if its still does it. Kinda weird, what do you guys think made it go away?

 

Clogged injectors? Low fuel pressure?

 

Not sure. Do you guys recommend using seafoam? Only thing I've ever used in my truck for the fuel system is the lucas oil, techron and marvel mystery oil in my gas tank. I've read mixed reviews on the seafoam so haven't tried it yet.

 

No, no, HELL NO! You would be better off sending the seafoam money to me instead of dumping that crap into your truck.

If a change in tune made the problem go away you're going in the right direction. Try setting it back completely stock and see what happens.

 

E85 burns a lot cooler than regular gasoline. That could be an indicator of bad cats. It could also mean the intake system needed cleaning too. You'll find out when you go back to 87 proof gas.