Hello Everyone. First timer here. I just picked up my first F150. I got a 2006 FX4 SC. It only has just under 78K on it. So my OCD mandates I do all sorts of maintenance to vehicles, weather its necessary or not.

First off, the truck runs and drives great. There is a hissing sound under moderate acceleration. Believed to be a vacuum leak. Going into dealership tomorrow to check it out. Other than that, runs perfect. No stuttering, or hesitation.

So not being sure of the history of this truck, I have done the the following so far. Cleaned the MAF. Replaced the Fuel Filter. Drove it for a couple days with no issues. Engine seems a little snappier than when I first got it. Just having fun, I've been romping on the gas from time to time. Just getting a feel for it.

Then decided to put in a bottle of Techron Concentrate just for good measure. Did the 20gal treatment, more like 18gal in there, added Techron, then added 2gal on top of it. For the past 2days the truck runs & idles just fine. Even when under light to moderate acceleration everything seems fine. But when I stomped on the gas yesterday, the truck hesitated bad and barely, and I mean barely accelerated. Thinking "that's not good", I tried it again, same result. This time then the Check Engine Light came on, blinked for a number of times, and then went away.

Truck has still been running fine ever since. This morning again, on my way to work, decided to step on it hard. Same thing, just hesitated again. No check engine light though. Its going in the Dealership Thursday for that pre-existing hissing sound.

I understand this stuff is pretty powerful. But what I don't know is what it does to the dynamics of combustion when its in the fuel. All I know is, truck ran good before this stuff. Put it in, and now I can't slam the gas without fear of hesitation and the CEL coming on.

Does anyone have any ideas what may cause this under these particular circumstances? Could it be carbon deposits breaking free under higher RPM/combustion when accelerating? Anything I should NOT do? Or check out? Anything should have the dealership investigate possibly?


Thank you in advance

 

Take it to someplace that will read the code behind the CEL and you will have a better idea of what is wrong. Autozone or other parts stores will do this free.

 

Has nothing to do with the Techron. Have the plugs been changed?

 

without knowing the service history of this vehicle, I'm guessing they are original. As suggested by JR105, I'll take it into Autozone or someplace and have them check any codes, for free.

Likely I'll end up changing the plugs anyway with a 1-piece design. I had a 3v 4.6 in my 06 Mustang and couldn't stand that two-piece plug design.

 

Those 2 piece plugs are very well liked by these engines and breakage is no longer a big thing. They are all I would run. Just do not get the E3, if you must have one piece, get the Champions.

 

Techron treatment likely had nothing to do with it. I wold also be looking at changing the plugs, just get the Motorcraft SP-515's and apply the anti-seize and you'll be fine.

 

Get the hissing/possible vacuum leak sorted out first. Maybe the Techron cleared a leak enough to cause an issue...

 

truck goes in today to dealership for the hissing noise. Meanwhile, stopped at Advance Auto, ran a OBDII scan, forget the code, but it was miss-fire in Cyl #5. So since the problem was intermittent, decided to buy a replacement coil. Changed it out in the parking lot. And wholah, so far so good. will test more and more on my way home, but did two throttle test and it acceled just fine with no sputtering or CEL coming on.

More to follow...........