Well I'm a little confused because ECO/MDS is never active while idling. MDS shuts off (regardless of load) below 24 km/h (say about 15 mph). If your truck is standing still idling, you're not using MDS ever.
Also my truck never holds MDS for more than 20 seconds sustained, unless I'm going downhill. Guaranteed if I'm on country roads or the freeway, it's always turning on and off in 7th and/or 8th gear. I don't know about city driving as I never drive in the city, but I'd imagine you could never possibly drive 30 mins straight in the city with MDS turned on; as soon as you hit the skinny pedal it's going to disengage again.
If you simply mean "idling for long periods of time"; well there is a guy on youtube (truck central) with a 2019 Ram and he works that truck hard, pulling loads that make his air suspension stop working. He also has nearly 1000 idle hours in addition to his other driving hours. No failed lifters.
So I really don't know about the whole idling = lifter damage thing. If that was the case, it should happen in every truck like clockwork. Certainly in a truck that has seen that kind of idling at 100,000 miles on the OD, that's a serious amount of idling.
Anything over 11MPH (17KmH) on the 1500s the MDS is active when your foot is off the pedal... and again it'***** or miss, there are plenty of cam failures with less then 100 Idle hours, and many with above. it's not an absolute defined issue, just read thru the comments in this thread, almost no two people have the same scenario.. I'm simply pointing out what are the known cause, what FCA knows is the issue, the environment in which they happen is still a hit and miss scenario .....we had a stock 6.4srt Auto 32k mile engine on the dyno, idling, just got done doing a base run for some headers test......thing started to clatter , we shut it off, opened up the 6.4 and found the #3 intake lifter had a seized roller.
personally My experience tells me If its going to eat a cam or lifter.......It's going to do it. and you the owner are just along for the ride....best way to prevent it ,do away with the MDS system in the truck, replace the lifters with NON MDS and Pull the plugs.
separate note, I've seen his videos , 1000 Idle hours in 100k miles in less then 2 years I find that suspect, because Both of our 2019 service trucks are over 100k one hit 100k in January and now has 124k the other hit it in March and now has 110k,irony is the 110k truck eat a lifter @ 19k miles and 15 idle hours , then a month later it ate a crank, there was some shrapnel left in the pan, we rebuilt it ,I wasn't going to let the dealer rebuild it, which voided the warranty so it's been warranty void for 89k miles ...... both of those 19s were months before his 4/26 posted video ,and nether one of those trucks is over 150Idle hours, our 2014 3500 6.4 gaser has 725k on it, 580 Idle hours and both of our 2016s are in the 400k zone and neither have more than 200 idle hours.
