i recently noticed that im getting worse mpg's while on cruise control than i do when i do not use it. this has not been the case in the past, and since i have the mds hemi i dont see how this can be a good thing. i have a previous post concerning some voltage spiking, is it possible that this is throwing off the mds or maybe something else entorely. and when i say its worst mpg's i mianing from min 3mpg to as high as 5mpg's

 

First and foremost, are you calculating your MPG by hand when filling up at the pump? Secondly, you can buy a tuner and disable the MDS if you want to try that.

 

not doing it by hand i have the console that has temp and mpg, milage and time

 

The OHC just averages out the MPG's. DO it by hand, you'll get a more accurate number. I don't think you're getting 3-5 mpg's...that's horrible!! If you are, there is something else terribly wrong!

 

ok can do, and sorry if i mis worded im not getting 3-5 mpg; that the difference i'm seeing between the 2 methods, i used to get 19-20 with mds now i get 15-16

 

So we can help diagnose your problem.....

Have you confirmed that you are getting voltage spikes (and have you been blowing bulbs as an indicator to this)?

Have you checked your tyre pressures (this can make quite a difference in mpg)?

When was your last service and are you using the correct oil (the MDS won't work properly on the wrong oil and also only works once the engine reaches a certain temperature)?

Some people don't like the MDS, however my experience with it is that, on long journeys at the right cruising speed (no higher than 65mph), it makes a significant difference on mpg's (I had 22.4 on the overhead on a 1,000 mile driving holiday, fully loaded with camping gear and family etc).

 

i ve got a list from the other post to help confirm the voltage spikes so thats in progress. tires are all set at 35 psi. last oil change was 2 weeks ago, i was running full syn 5w-30 from the begining but at last oil change i switched to the oem full syn 5w-20. will let you know on the results of the voltage issue.

 

Has your overall mileage gone down recently, or just when MDS/cruse is being used?

If your non MDS/cruse mileage has gone down i would point more towards routine maintenance like air filer and spark plugs and things of that nature.

nateroach