I recently purchased a 2002 Dodge conversion van with 100,000 mi on a 3.9L V6 engine and 3-speed automatic transmission with lockup torque converter. The EPA estimated fuel ecomomy is 13/15MPG.
I ran two tanks of fuel through it and started calculating fuel efficiency on tank#2. 12.5MPG in mixed driving, but heavily suburban and lots of short errands under 10 mi. Yikes.
I performed a complete tune-up (see my garage entries), synthetic oil, filters, lube, plugs, wires, cap, rotor. I also completely drained, flushed and refilled the engine coolant (2 gal Prestone extended life and distilled water balance). I raised the tire pressure from 34 psig to 42 psig. Tank #3 returned 14 MPG. Driving on this tank was about 50% highway with the balance suburban driving with typical errands under 10 mi.
I am still learning to drive this vehicle mindfully. I have driven a large variety of vehicles and they all require some adjustment time.
I installed a BAFX Products (TM) - PIC18F2480 Bluetooth OBD2 dongle and control it with the Torque app running on my Android phone. It allows me to monitor more parameters than I care to. Mostly, it allows graphing fuel efficiency feedback while driving. I get immediate feedback of my driving technique on MPG and I know this is influencing how I drive.
Since I installed this halfway through tank #4, I expect to see improvement through at least tank#5. Tank #4 gave 15.6 MPG.
These results so far are consistent with EPA data for this model. I can see they are improving, but I am looking for 18 MPG.
I'm afraid that I am confined to mostly short trip driving for the rest of the week. As I develop a strategy for driving a gas pig, I will share what I learn. I welcome any feedback or suggestions.
looks like you're ambitious to work at it. One thing to consider is when you look up the EPA ratings, you're looking up the ratings of the vehicle they cut up to make the conversion vehicle. Most often the conversions have stuff like raised roofs, fender flares, running boards, and added weight of extra interior trim (often times oak in conversions) plus the weight of fancy captains chairs, TV's, VCR's, DVD players, Game consoles, seats that fold into beds... If you can make it meet the original EPA rating you're already doing great. If you can exceed it by more than a narrow margin, then you're doing an exceptional job.