96 caravan puzzling gas mileage (4cyl)

You'll always get the best average during highway use...even at 80MPH. But you should be getting much better mileage than that! Heck, I average 18-19 city and 26-28 highway with the 3.3 V6 Grand Caravan! Have since I bought it new 8+ years ago. And have gotten as high as 29-30 on some highway trips!

Everyone tells me the 4 cyl "has to work harder" than the 6; and that's why it gets less. I have always thought the van was geared lower than most; but I've had it in the shop and noone agrees-- guess I'll have to stick to the dissapointing MPG

Apparently so. I wonder what the point is if a 4-cylinder has less power AND worse gas mileage.

My engine runs at ~2000 RPM at 60 MPH. You can use that for comparison. It's possible that you have the 3-speed tranny instead of the 4-speed overdrive.

I always thought the four-bangers were awful puny for a vehicle of that size that's supposed to carry around a family. I did overhaul one once, however, and I thought the power was actually halfway decent, but I suppose one could expect that with a fresh engine. Anyway I agree--what's the point of a four cylinder since they don't get any better gas mileage, have less power and even generally wear out sooner? They're even less safe as their power wanes with higher miles.

It makes perfect sense to me. You drove it more on the highway than usual, and when it's cruising along, even at 80mph, it will get better fuel economy than in the city where you are stopping and going. Remember that any time you are sitting at a stoplight, even though it's not burning very MUCH gasoline while idling, you are still getting ZERO mpg; and when you accelerate from that stoplight, the mileage you are getting is very low AND it's burning a lot of gas at the same time.

The four-cyl. engine may burn MORE fuel in city driving, driven to equal acceleration as a 3.3L V6.

If you were to cruise for 10 hours at 80mph, you'd get even better mileage than you did for those two straight days.

Right-- I do have the 3 speed. I understand that that particular transmission is more reliable than the 4 speed-- so maybe I'm lucky in that respect

And have you checked your tire pressure? change your air filter recently? Do you always use it for deliveries? If so what are you delivering. If you are loading it up for deliveries, that would mean you are adding weight to the van, and that would increase your mileage. And if you are mostly arounfd town, it depends on ambient temperature, grades of the road stop and go, utilizing air conditioning, etc. Have you changed you O2 sensor?

I've done all of those things, except replace the 02 sensor. That is what is puzzling-- the bad gas mileage is from normal driving-- my wife everyday for normal wife stuff. It improved when it was used to deliver things--

10 hours of not being turned off; city driving; and the increased weight of delivering retail fixtures. Makes no sense-- but one thing is for sure-- it's been like this for nearly 5 years!

David: Why would weight add to my MPG?

What he stated was backwards. Adding weight will decrease MPG.

Sorry, I mean it will increase your mpg. If you haven't changed your O2 sensor, you should. After all these years it is probably not working correctly. It should be routinely replaced to ensure your vehicle maintains a good air/fuel ratio.

I think you mean DECREASE

My neighbor works at the dodge dealership; his diagnostic equipment has never indicated it needed changed; but they're not much $$-- wouldn't hurt I guess.

Most of the time, a bad O2 sensor will not set off the check engine light. It needs to be tested to see the actual waves it produces for modifying the air fuel moisture. Over time with all of the exhaust residue it will be harder for the O2 to correctly meter the ratio.