Sluggish 2006 E450 6.8 10 cyl

Well there's screaming and then there is REALLY screaming.

Even though it may sound like a jet engine, turning 3500-4000 RPMs is NOT screaming.

If you were turning more rev's than that, you were likely trying too hard to keep your speed up higher than necessary.

Hmmm. Filter could definitely cause under-fueling!

Engines need fuel, air and ignition.Changing fuel filter and air filter may improve performance, the fuel pump (located inside the fuel tank) may be defective. Usually, hard starting indicates possible fuel pump problems. Have truck service check fuel pressure and ignition system as part of a tune up.

Thank you SO much to everyone for sharing their knowledge! It’s kind of overwhelming to sort through it all to figure out how it might apply to our situation! Your information points to our lack of experience – your efforts to get us pointed it the right direction through a process of elimination is appreciated! The sluggish idea came, in part, from people’s comments with the same RV/engine – sounds like it’s not totally out of line with other’s experiences here. When we first started driving ours – we were powering up a mountain – as you say with the engine screaming – the engine shut down – and we had to be towed to a dealer. The computer showed injector codes – which could not be replicated at the dealer. Only definitive thing that thing that showed up was a blown fuse. This hasn’t happened again – yet I guess we hesitate to push the engine until it screams because of past experience. Oh – did I mention we hadn’t purchased roadside when the engine quit? Talk about live and learn! Re: the flatlander reference - please remember we're used to a well oiled machine ;) We did read and think about the tuning programs - but didn't know if it was something we should pursue or if there is another problem. Fuel filter has not been changed - so I think that's something we will have done.

Haven't climbed a steep grade in a while with our 2004 27 foot rig but 45mph at high altitudes sounds about average. Might have rig dyno tested and tuned if needed. A 27 footer loaded with full water tank and stuff for camping etc., will not climb hills as well as a 24 footer carrying less stuff. I hate listening to a screaming engine, rather take my time climbing.

X2 on the 5 Star Tuner. I put it on our 2005 31' E450 C and it made a world of difference in shifting, climbing and MPG. When I left to the tranny to its own shifting it was terrible, wouldn't shift when it should, dropping to really low RPM before shifting etc.

Now I can keep up with the DP guys on most hills and get better shifting and mileage while I'm doing it. Drives almost like a car now!

Dave

I have a 2008 31ft Four Winds E-450.I live in Tn.at the bottom of Jellico Mountain that is on I-75 on TN and Ky. line I guess a lot of people here will be familiar with the mountain. Start at the bottom towing my Honda CRV and holding the pedal to the metal I can top the mountain at 60mph.I mean the pedal on the floor all the way. I don't know if this helps but I don't think that is to bad for the weight and towing CRV 3000lbs.

Tow/Haul mode in our original OEM 5R110 tranny (Ford 5-speed TorqShift) since day-one resulted in a bit rough/jerky shifts, so I minimized use of Tow/Haul mode to keep things smooth. I ran our Class C at 55-60 MPH highway speeds up all kinds of highway grades at all altitudes and just rev'd the V10 well up into the 4000's whenever needed to do it.

HOWEVER, our OEM 5R110 tranny gave up the ghost big-time at only a little above 61K miles. Neither of our two excellent mechanics could understand why (the tranny fluid was still a healthy pink color) an under-loaded E450 chassis blew it's transmission at that low of a mileage regardless of how I had driven it.

I had them replace it with a remanufactured heavy duty version of the 5R110 transmission. This 5R110 transmission, for some reasion, upshifts and downshifts smooth as butter when in Tow/Haul mode, so I now drive it almost exclusivelly in Tow/Haul mode - hoping that this tranny will now last "forever" regardless of what RPMs I run the V10 at. :S

(I hope that what I said above won't discourage V10 owners from tapping into the V10's total capabilities via it's high RPM range ... as I think that my original OEM transmission blew due to a manufacturing defect or my non-use of Tow/Haul mode regardless of engine RPM ... thus overheating the transmission too much from excessive torque converter slippage pulling up long grades in hot weather.)

pnichols wrote:
Just for what it's worth, we traveled on highways above 11,000 feet in Colorado last fall. Our E450's V10 didn't even grunt up there moving our Class C right along keeping up with the diesel tow vehicles and little SUV puddle-jumpers around us.

However, our 24 footer probably isn't more than 12,500 lbs. fully loaded - including the DW's collected rocks.

X2 Been there done that... although our 2012 E-350 Nexus Class C has GVWR of just 11,500 which we usually are very close to and I often tow my Harley - bike and trailer are about 900#.

Still will never understand why no-one seems to actually read their owners manual. :h

How else can you explain the large number of folks who do not use Tow Haul and yes, unless you are running nearly empty/very light you should be using it all of the time. The many benefits of doing so apply going both up hill {and frankly especially} downhill. :S

The V-10, especially with the newer transmissions, is unbelievably bulletproof "If" you run it as designed by the engineers at Ford {can you spell Tow Haul?}. :B

Just for what it's worth, we traveled on highways above 11,000 feet in Colorado last fall. Our E450's V10 didn't even grunt up there moving our Class C right along keeping up with the diesel tow vehicles and little SUV puddle-jumpers around us.

However, our 24 footer probably isn't more than 12,500 lbs. fully loaded - including the DW's collected rocks.