I have an 09 1500 Crew Cab w/5.7 Hemi. Fuel saver works great up to 45 mph. At 55 mph it's hard to get into fuel saver. At 60 you have to be going down hill. Same for the overdrive. At 65+ fuel saver won't hold on level road. Overdrive kicks out on freeway overpasses. Can trans be adjusted to require more pressure to kick out of OD and fuel saver?

 

The truck is too heavy at higher speeds and loads. A true 4 cylinder motor would struggle to start your truck from a stop, let alone move it well at highway speeds.

If you were to be able to keep it in 4cyl mode, the truck would shake, imo.

 

The question you should ask yourself is your truck getting gas milage similar to others. Mine is an early build, so I don't have the fuel saver light. My milage is within range of what others have posted for city/hwy driving. Pickups are not noted for great mpg.

 

are you talking about mds? it works best at highway speeds to save milage. my friend gets 21 at 60mph in his 09 ram 5.7 eagle hemi

 

I recently swapped a motor out of my 2009 ram 1500 5.7 4wd with a 2013 5.7 and have had issues with the truck kicking the check engine light on for a cylinder 3 miss fire when I’m accelerating over 3.5 rpm on occasion. It also occasionally has a rumble at cruising speeds around 55mph which I believe is the truck trying to put itself in fuel saver mode but doesn’t. I have 31 off road wheels and tires on the truck and from threads I’ve read said that the truck will do that because of the alteration in wheel size. This morning I jumped in the truck and drove to work with no issues. Stopped and filled up with fuel and pulled out and it acted like I was only running on 4 cylinders with little power so I pulled over. Shut the truck off and started back up (engine is hard to crank when warm) and seemed to run on all 8 again with no issue. Anyone have any ideas?

 

Was this ever resolved? I am having the same problem. We just bought the truck and all of the sudden fuel saver no longer comes on above 45 unless going downhill. It is getting crappy gas mileage too. Seems to labor to get into overdrive too, but all other shifting is very smooth and spot on. Transmission was serviced recently at a trans shop before we bought it. Changed speed sensors and there are no odb codes. I have also changed all the spark plugs. Could the shift solenoid pack be causing this? Something else?