Which way you're going matters sometimes.........here is my take on it (from another post):
I have a (first gen) '94 FORD Explorer with 4.0L ohv, 4x4, 4dr, auto trans, 3.27 gears, and P235/75R15 tires (34 psi), no modifications at all. It has 140K on the odometer. Factory says it's a 19 gal. tank. I use regular Dino oil and reg. unleaded gas.
We went on a long trip, from Vancouver, WA to Anahiem, CA.......it's alittle shy of 1000 miles (one way)......I did most of the driving, w/ my wife and 8 yr old in the vehicle.....she would drive when I got tired. I got onto the freeway (I-205) and it was a straight shot to I-5 all the way down to CA. Same route back. Minor side trips off the freeway to fill gas or shop at stores (just off freeway). Took about 17 hrs. one way. Total average MPG for the entire trip was 18.549 MPG.
Observations:
I noticed that on the trip to CA I got terrible gas mileage (maybe the vehicle was resisting going to CA or the head winds). Anyway, I got an average of 16.97 MPG......and the computer did show a "check engine light" just past Sacramento, CA to Anahiem, CA.......it would go off and on and off and on, again......don't have a reader (BTW, on the trip back it activated only once).
On the trip from CA, back home to Vancouver,WA.....I averaged 20.05 MPG.
There were two times of the trip back where I got 21.39 and 21.40 MPGs (CA valley area/70 - 75 MPH).......that same area on the way to CA I got an average 16.23 MPG (maybe the head winds?). And, on the way back I did have to use 4x4 once when I was at Mt. Shasta (caught in the snow). Going up Mt. Shasta and most of the way back, was in the rain. On the way to CA it was mostly dry when I hit the CA border.
There are some folks here, that say their vehicle USED to average about 300 miles or so when the gauge was at 1/4 tank....that is actually good. Though, IF I had a broken gauge, I wouldn't trust that method to calculate when I needed to re-fill my tank.....not after seeing the MPGs on my vehicle go from a low of 15.11 MPG to a high of 21.40 MPG.
Oh.......TOTAL cost in gas for the entire trip.....$263. The most expensive gas was in CA and cheapest was in OR........I've seen reg. unleaded priced as high as $2.89 in CA (in Anahiem I found $2.37) and as low as $1.95 in OR.
As for the "check engine light" on the way to CA. I figure that the loooong drive w/o a long cool down may have contributed......or maybe it was the cruise control set at 75MPH, or the head winds that made it harder for the engine to pull the vehicle? On the way back home I didn't use the cruise control......and the "check engine light" activated once (early in the trip).......as for "head winds" comment (no science to the comment)......it just felt like the vehicle rolled alot better when going home to WA.
Sorry......don't want to HI-JACK this post but, I figured that I could add my .02 observations......from the perspective of a stock first generation (areo dynamics of a shoe box) '94 FORD Explorer with 4.0L ohv, 4x4, 4dr, auto trans, 3.27 gears, and P235/75R15 tires.
Aloha, Mark
PS.......When going over the mountains......this vehicle is a "dog." If I had known before the purchase that it would be that hard to keep a reasonable speed (55-60 MPH) going up what is about a 5-6% grade (that is what the sign says going down) I would have gone with MORE HP (another vehicle). The 4.0L ohv (at 160 HP) in this vehicle doesn't cut it........you have to floor it just to maintain the speed while going uphill (mountain).........but, traveling around town (flat areas) it's OK.
