Not going through the whole story just a brief. 2013 4x4 ecoboost at best 9.8 mpg. The dealer finally looked at it, found metal in oil, replaced motor with new long block took them 3 1/2 weeks. Left the dealership driving like there was an egg between my foot and go pedal. 4 mile of freeway going home. Re-set instant mpg,driving between 60 and 70. About 2 mile from freeway exit to home pulled in the drive looked down to see 21.6 mpg. Have about 800 mile on it now. Took a 500 mile trip for xmas , still breaking in , driving like an 85 yr old grama ( stiil not trusting the ecoboost). Varied the freeway trip between 65 and 80,mostly running between 65 to 70 changing speed and rpm every few miles. accomplished the 500 mile trip on 1 tank of gas averaging 20.3 mpg for the trip. ah much better. Now if the mileage improves as much as some of you say once I get 3 to 5,000 miles on it, maybe I 'll see that kind of mileage running 80 plus all the way. no more lol

 

Personally dont baby it. Once the oil temperature is up drive it like normal. If you baby it you arent giving it the right chance to break it in and you aren't driving it like normal seeing how the new motor is.

Congrats on getting a new crate though.

 

I agree, I drive mine hard for the break in period

 

Good to see things worked out for you. I second not babying a new motor. Don't flog the crap out of it but let it rev then let the RPMs drop. The new rings need to seat and doing this will help the process out. Once it has a few hundred miles on it start dropping the hammer more, if something is going to let loose better now than later.

 

Agree with all the people above. No reason to baby it, Get on it and go!

My truck didnt make it 100 yards off the dealer lot before my foot was in the carpet up to 100mph.

8 Month's later and 18,900 miles shes still running perfect and popping off 17 to 21mpg every tank. It's Been running so good I decided to get it custom tuned since i dont have any worries about the engine.

 

If you are unsure about how to do it. Long story short, dont let anything sit at a specific RPM or throttle position. Most important thing, not only during break in but during any other time is to make sure the oil temp is up. Coolant is NOT always a reflection of oil temp as well. I usually wait until it is up to coolant temp then give it another 3-5 minutes. After that. Go to town. The motor is designed at this point to run hard. If you want proof of this, MB and BMW have oil temp sensors and their vehicles are limited until the oil is up to temp. The older M3 actually had lights that would vary where the redline of the car actually was as it warmed up.

Here is what I have done on every new vehicle I have owned and had no issues with any of them.

http://www.mototuneusa.com/break_in_secrets.htm