O4' Grand Caravan SXT. Getting poor gas mileage like 19 mpg on hiway, 12 city!! I've checked the coolant temp with my Mac Tool hand held and its between 192-203 in 0 degree weather here in southern ontario. No service engine lights. Change the plugs, put a set of e3's in(think I wasted my money!). The plugs I took out were burning white, which is good!! Wires in good shape. Cleaned the throttle body. No fuel filter on this van to change, its in the tank. We bought this van 7 weeks ago and change the oil at that time. Change the oil again tonite and put synthenic back in BUT the oil smelled of gas real bad!? So its overfuelling but the plugs are white??? The exhaust has a very very faint smell of rotten eggs, so I dont think the cat is plugged. I took it out for a spin and no change. I have a K&N filter coming in tomorrow but I dont think Im going to get 10-15mpg back!? Can someone tell me if I need to replace CERTAIN sensors without throwing parts at it!? With the hand held I watch the changing of the upstream O2 sensor and it was moving alot which it is suppose to do as the downstream O2 moving very minimal. K I'll check back tomorrow!! Thanx for everyone's help....

 

your problem is: it's very cold outside. the colder the weather the worse the fuel mileage. in cold climates, the fuel is changed to reduce line freeze. this fuel does not generate as much energy which also reduces fuel mileage. sounds like you have the right tool to test all the systems. now get a factory service manual and follow the procedure for addressing fuel consumption. this will give you all the answers you seek and won't have you replacing any unnecessary sensors.

sensors that affect fuel mileage. ect, tps, iat, map,
components that affect fuel mileage. ignition system, fuel system, egr, cat, air filter (good thing you bought a K&N that will lighten the load on your van buy reducing the weight in your wallet)

 

I know somewhat, what effects the fuel mileage but no way does it take 10-12 mpg away on the highway. I just sold my 1996 Grand Caravan with 425000kms on it and it got 27 mpg on the highway @ 65 mph, no matter what the season was. I will try and find this manual for addressing fuel consumption, I've never heard of this manual before but I'll ask a good friend at a Chrysler dealership and see if there is one. If not then what? Also this van does not have an EGR solenoid on it either. Thanx

 

you said 19 on the highway... HTF are we suppose to know YOU, your driving style, roads, etc. ever heard of the claims "your mileage may vary" ever check to see if you have brakes dragging? how about tire pressure? how about exhaust back pressure? there's no "manual on fuel mileage" there's fuel mileage concern diagnostic procedures in shop manuals. I've even seen this in Chilton manuals.

 

Hey Sap!! You here to help?? just wondering cuz it sounds like you know everything!!! YOU must be a god in your mind!! driving style is set the cruise, you know what cruise is?!?! ya at 110 km/h for like an hour. And as for your comment on manual on fuel mileage I quote "now get a factory service manual and follow the procedure for addressing fuel consumption" sorry if I worded my sentence wrong but f#$%off!! I came here for some input not to be harassed by some piece of little s%^t thats still f#$%in green!!

 

Hessapp.
Just because your last post that make me can not resist to post reply.
The service manual, driving style, tire pressure will not help with this problem.
For now my recomandation: Oxygen sensor(before cat.), next Output sensor, the one on the left side transmission(looking from front), to save money you can have those sensors from any chip sources, I bough my O2 $55.00 from Autozone, and O2 $125.00 from Dodge Stealer, they both performed the same.
I wish you live same town with me, so I can lend you lots of sensors and tools.
Wish you luck.

 

LYLY!!! Thank you oh so very much!!! This is just the type of feedback I was lookin for!! I replaced my upstream O2 sensor(the 1 before the cat) last nite and put a K&N air filter in and no change. You said next output sensor, the one on the left side transmission. I was just wondering what sensor you were talking about? I appreciate your input LYLY! Thank you! Also on Monday nite coming Im doing a leak down test on the injectors to see if there is a problem there!!

 

I don't think leak down test on the injectors will help, but if chip or cost not much money and you have time.
(leaking injectors would've caused error codes)
The sensor I talked about is Transmission Output Speed SENSOR, OEM part number 04800879, about $30.00 Ebay.

 

Hey LYLY!! Perfect!! Ill inquire about that on monday!! Thanks again!!

 

The Transmission Output Speed SENSOR is on the right not on the left(input) as I said before.