OK, I have the 5.4L engine and man does it still feel "tight" after 800 miles. I've followed the break in suggested by the user manual of varying speeds. But now it's time to open up the throttle. I started tonight by warming up, then giving it the gun. Then I break hard and slam the engine some more. I alternated between smooth and harsh driving. For example at a stop light I would gun it and get it going as fast as possible, then slow down rapidly, then gun it up to speed again. What's funny is my 4.6L engine I ran in the XLT was much more easy to crank and felt "free-er" (if that's a word). We'll see if my experiment works as I plan to torture the 5.4 this weekend all weekend long. Got to loosen this baby up somehow. It seems to cry for this.

 

When they describe driving at various speeds they don't mean "harsh driving" as you describe. Braking hard, for example, really does nothing to help the engine "break in." They mean to do just as they say - drive at various speeds. Don't spend lengthy periods of time droning down the interstate at one set speed. Drive normally.

As for your plan to "torture the 5.4 this weekend all weekend long" I would have to say it's probably not a good plan.

 

Thanks for the input, but it is not like I just drove it off the lot. It's now at 818 miles. I did vary the speed nicely (except for a few blasts of speed here and there) for the first 800 miles. I think that's plenty of soft driving. I need to loosen up the tight feeling of the engine to unleash the full potential of the horsepower of the engine. I'll blast it for the weekend and then Monday see how it drives normal style. Can't hurt it any, it is built pretty tough.

 

ummm.. interesting.. I have built plenty of crazed racing engines (cooks automotive, carson CA). We hold many land speed records and built world class race cars but never have we ever had to "loosen" an engine to make HP. We broke it in on a dyno, did the tune up there to get peak HP.. and how can you get more HP after that??? A motor is either built right or wrong. If you arent realizing the performance you are looking for there is probably something wrong.. not enough fuel, air, gearing wrong, or something.

I would look elsewhere for your problem before torturing the motor and breaking what needs to be fixed now.

Bdd

 

I don't really see this as a hp or performance problem. I guess I'm not good at describing what I feel. It "feels" like the engine is tight. It runs great and has hp, but I "feel" it could be and do more. I like a "looser" smoother feel to the engine. I've decided I'm going to extend my "torture" sessions on the truck untill next Sunday. The good news is I live on the outskirts of my city, thus I can give it a real rough going over. Lot's of long steets between traffic lights. I just have to watch for cops. That'll give me a full week for a real break in. Then, when I'm done I'll take it in for it's first oil change. I'll report back on how this experiment works out.

 

roflmao! Your way of treating your truck is a bit bazaar! Never in my life have I seem such an approach, but I say go for it though as long as you don't mind driving a beater later.:O)

 

Why don't you reset the PCM? Its probably you have been babing it, and it has learned to upshift too soon.

 

This is the reason why I don't buy used vehicles. You never know how they have been treated!

 

why dont you just drain the oil, crank it up and put a brick on the gas pedal. that should loosen it up a little

 

From what I have read, the 4.6 revs higher and quicker than the 5.4.

I know these engines are tough, and I admit to flooring my truck at least once a day, but you do have to be gentle with these in order for them to last...

 

I think the first word in the title of this thread is the most telling.

 

the hard braking on a nearly new vehicle will/can cause premature rotor failure from glazing and heat issues. Changing speed is not required to break in the engine, main thing is to vary the RPM's which can be done at low speeds by using the tow mode or a different gear. Anyway, let us know if the engine loosens up and if performance improves.

 

With the long term reliability of your truck in mind...

You should just keep driving normally. Hard acceleration, hard braking, followed by hard acceleration isn't going to do anything good (loosen) for your engine except cause excessive premature wear on the transmission and brakes.

 

I agree with vcrisis311 fully. And make sure you take a vid of it so we can make money on funniest video shows.

Its your money man.. if you treat your body like that can I get some insurance on you?

 

Well, I must admit I'm surprized by this response. First off, I doubt there's anything I can do that will destroy this engine, it is a brickhouse solid. Second, maybe you're getting the wrong impression. I'm torturing it, but in my case it's not as bad as you guys think. I'm a very conservative driver by nature. So my "torture" is probably light compared to how some treat their trucks. Second, the truck already has 850 miles on it. It needs a little punching now and then. And finally, the truck seems to be running more "freely" since I've started the experiment. And come Monday I'll be back to babying it and give it an oil change next week. Some people drive like maniacs from day one and still get 100,000 + miles on their trucks. Just so long as you keep up maintanence and fluids, it'll be fine. But I do thank you all for your concern!!!