when im sitting in the driveway the car says like 5 mpg and jumps around 16 mpg's when im cruising. car has pulley and intake. is that normal for a modded car? i wouldnt think so but i dont know much about mercedes and there computers. also fuel pressure is 5.something before i crank the motor. from what i understand, thats higher than stock.

 

too many variables -- but there was a thread recently on MPG == mods and driving styles = a large range. When the car was stock/modded you can get 9/5mpg if you are driving hard -- cruising freeway stock/modded 24/19mpg.

I have no idea about fuel pressure -- Do a search and learn more about MPG and fuel pressure.

what size pulley and tune do you have?

 

Look at the average speed on the display to see what your average speed was. This is pretty accurate if you drive somewhat tamed. When my display reads 16mpg, my average speed is usually between 34-37mph (after start). In the other thread, I stated that my mpg is 14.5 at 24mph average speed. I always laughed at how the computer figures I could get 5mpg in park though.

 

The display is average, not instantaneous. If you want to see what it is in real time while cruising at a steady speed, just pull up the screen and hold down the ODO reset button for 3 seconds. If you do it while parked it should stay at 0 until you've driven a little. I've found that while cruising down the interstate it takes a couple of minutes for it to move around and finally settle on a number.