I just got my new F-150 a week ago and the engine and drive train seems tighter than the '02 I traded in was when it was new. How long before it loosens up? I went from a 4.2 W/5speed, 4wd to a 4.6 auto 4wd.

 

Most people say they are tight up to 15,000 miles. I've taken two there, and can't say that I noticed it that much.

Remember, you need to accelerate hard to seat the rings good. Don't baby it because it's new. Lots of stop and go lights.

 

I remember reading that the new engine in the 2004s was similar to the Mustang engine, and that the Mustang engine took about 3,000 miles to be broken in. It was a thread a lot like this one, actually. I believe that it was Mike Troyer that answered and explained it, but I may be wrong.

 

I had an '02 F150 with the 5.4L and it felt tight up until about 10,000 to 12,000 miles. Then it suddenly seemed to loosen up and run better.

I had a '92 Ranger with the 3.0L V6 that was tight until 90,000. Then I set the timing up and started running it hard and it loosened up.

 

Thanks Fella's! Looks like I 've got to get some miles on before it starts to free up. I was judging mine by my brothers '99 that had the same engine and tranny. He said he was smoking the tires and getting around 22mpg almost fresh out of the box! I said he was full of BS. He had to go out and get a new '03 F-250 W/ hd suspension, 5.4 , 4 WD and 4.11 rear end. Said he just liked the feel of a bigger truck. Again,I said he was full of BS and was just making up for a lack bulk in a certain appendage!
Thanks again!

 

My 99 5.4 didn't really loosen up until it had over 20K on it. Maybe using synthetic oil contributed to that. Mileage suddenly jumped up 2 to 3 MPG @ about 25K.