Yes, are does sound like it went into reduced power. Should have been a message or light on the dash. Often a key cycle will restore it to full power (for some amount of time, until/if the problem reoccurs). As such, if it happens again, stop ASAP, turn it off, and start it back up. Forced idle is meant to do nothing more than that. Lets you pull over with power steering and brakes basically.
(And as you're already working on, should be a code stored....)
I honestly think that your only problem was that you did not move your transmission down to second gear when you started the climb. Your engine was losing RPMS and therefore sensed something was wrong and either quit climbing because you were not maintaining the rpms and losing speed or went into limp mode. We live on the top of a rather steep hill and keep our MH at our house. There is no way we could climb that hill unless I shift down to second gear. I can easily maintain my rpms and speed while climbing the hill in second gear. I do not use tow haul for anything but descending long grades of usually 6% grades or better or downhills with a lot of curves. Just remember when starting a significant climb at slow city type speeds you will need to shift down before starting the climb not matter what type of engine, gas or diesel, you have when pulling that kind of weight.
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Mike & Charlotte
2014 Newmar Canyon Star 3610
Orange County, California
Two years ago I drove US421 from Virginia into Harlan county, KY...accidentally. 24 miles (12 up and 12 down) whatever that mountain is with hair pins and all kinds of craziness. 2008 v10 E450 chassis (non-winnie) 30 ft with a 7000 lb trailer with a Jeep and golf cart on it...with the a/c on. Also, it had just rained.
I will never do it again in an RV. There should be a warning at the start of it on either side.
Anyways. The v10 ate it up. No issues. I kept the gear selector in 2nd the entire trip.
Your v10 should've made it up that hill.
mac 'my stomach was turned inside out' gyvr
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2001 Winnebago Journey 32t, towing my golf cart and 04 Jeep Wrangler Unlimited to places I never dreamed I'd be able to go to. NAXJA President
More food for thought. Not sure but maybe the transmission talking to the motor? I believe they do communicate on the newer chassis. Gear to tall for hill? Maybe tranny caused the engine derate? In any case always downshift prior to going up a really steep low speed hill or driveway. Get the gear ratios working in the engines favor.
Your profile doesn't mention what year motorhome or the size chassis you have. If it's an early 2000's model there was a TSB about a false overheat condition. When the condition appeared the engine wasn't actually overheating, but the temperature sensor thought it was. When it happened the engine would go into limp mode.
I would definitely take it to a Ford dealer and have it checked out. We've gone through the Icefields Parkway in British Columbia with our current motorhome without any problems. Going north there are several miles of 6% and 7% grades. We also had our 2001 motorhome in and our of Skagway Alaska. That's a 12 mile stretch of 12% grade. Again the motorhome handled it with no problems.
Its a 2013 on a 26k chassis. The hill was in a neighborhood and hidden at a turn. I was going slow. It cant be compared to going through mountains at highway speeds
I did a similar climb in my ole class C. I slowed down, forced it into 1st gear (automatic tranny) and held the speed that gave me 4500 rpm (about 5 mph). In a way, I was kind of surprised it made the climb.
__________________ 1999 Fleetwood Southwind 35S (Ford F53 6.8L V10) - Toad 2003 Saturn Vue.
It won't do MACH 2, but I can get a sandwich and take a pee.