4 weeks ago I bought a 35ft Class A 2010 Holiday Rambler on a 2008 Ford F53 V10 6.8L 22,000 lbs chassis with 22.5 inch tires.
It was driven from Indiana 3 weeks ago and had 442 miles on it when I picked it up.
The dealer filled it up with fuel for me and I have driven 300 miles.

Until last month I had 1999 Ford F53 36 foot Class A motor home with the V-10 6.8L (the old 2 valve with 90,000 miles on it) and it had the Banks Power Pack. So I understand how it’s supposed to work.

What I have found since picking up the new one, is that under heavy load (long hills, 2km long, in 2nd gear, WOT, about 4000+ rpm and about 40mph or 70kmh) it starts to surge. A kind of wah, wah sound and not building any more power. The farther you get up the hill the worse it gets until you back off the throttle. (Obviously it’s not hitting the RPM or speed limiter) There is no check engine lights on at this time. I hope it is old fuel and lack of use (although it should have had at least two tanks of fresh fuel through it before my dealer got it and filled it up for me) It’s been OK while passing but haven’t had the chance to lug it again up a long hills. Because it’s an RV, I don’t get the chance to drive it a lot, little alone lug it up big hills, until we go south at Christmas. The mountains through Virginia will tell me if it running properly as I know my old one would keep the speed limit plus all the way through.
That would be a bad place on December 24th to find out you can’t crawl all the way to the top.
I’m thinking one more tank of fuel and then trying to explain to a Ford Tech with his scan tool that it really doesn’t run right if he will let me drive it on a big hill, with my foot to the floor, if we can find one without crossing the border.

I’m thinking one more tank of fuel and then trying to explain to a Ford Tech with his scan tool that it really doesn’t run right, if he will let me drive it on a big hill, with my foot to the floor, if we can find one without crossing the border. Any information to tell the tech to look for would be helpful

 

First, editted your post to remove all the Microsoft tags. Don't cut-and-paste from a Word/Wordpad/Outlook document, it always screws it up.

That sounds like a classic fuel supply problem. If it were me, I'd hook up a pressure gauge to the fuel rail and watch it while doing these long high-load situations and see what happens.

You might just have to change the fuel filter which is probably what I'd do first.

 

Thanks for the input. I'll give the fuel filter a try.
I didn't know about the MS Word and the tags can't see anthing different on the post but I editted out the post using email Hope that worked