Just an FYI before you go out and spend a bunch of money. The term "MMDC" refers to the type of dash system that you have, not necessarily a specific part. The initials stand for "Multiple Module Dash Control". Before you go out and pay someone over $100 bucks an hour, try this (I learned this at the Gaffney Freightliner school a couple years ago). Pull the back of the dash off to reveal the back of your dash gauges. You will see a bunch of wires with two running to each gauge. Remove the wires from each one and check that it has made good contact. If you can, brush or sandpaper the contacts. Slip them back on see if that helps the problem. Now here is the cool part.
The MMDC dash works with a single brain that sends the signal to each gauge. Each gauge has a separate signal that only works on that specific gauge. What that means is that you could pull all the wires off the gauges at one time, and IT DOESN'T MATTER WHERE THEY GO BACK TO. Yep, you can't mess up the gauge wiring because no matter which gauge wire you use, the gauge won't respond until it see's it's own personal signal. I used to have that dash on my 06' Meridian. I tested it out and it's true.
So flickering may be the brain going out, or you may just have a loose wire. Either way you can check it out without fear of mixing up the dash gauge wiring.
Sarge