I have a 1996 Plymouth Voyager that I have managed to keep on the road, if only for a winter car. Recently, I noticed I was going through a lot of gasoline. Figure I am getting about 5.5 miles to the gallon. It is only a 4 cylinder and I do not smell gasoline so I can’t figure out what is going on here. I have had a leak in the fuel filler in that I couldn’t fill it to the top or it would pour out, but figured it was a leak in the overflow. Don’t want to spend another dime on this thing. My other car is a 2009 Nissan Altima coupe so I rarely drive this monster. Thanks!
all sorts of things can cause poor fuel economy, from sticking brake calipers to a leaky fuel lines. Some of the things that can cause this are extremely dangerous. You’d need to provide more details (how’s it running, any codes, any tests you’ve done) before we could advise.
Trying to avoid bringing it in to the service station. It runs OK except for an exhaust leak. Rusting out pretty badly on the sides…well, really all over. Even had a wheel rust right through. My ex wants our 17 year old son to drive it and I say it is unsafe. Bottom line is I think he want our son to drive the first 6 months on MY insurance before he gives him the SUV he bought for him on HIS insurance.
I’ll have to put some gas in it and look underneath while running and while idle to see if I notice any gas leaks.
Oh…and it has well over 200,000 miles and new brakes, shocks and tires.
That 2.4L Motor Is An Efficient One And Should Be Delivering Up To 26 Or 27 Miles Hwy. You’ve Got A Problem That Should Be Very Obvious To Anybody With A Little Savvy.
How’s your car I.Q. ? If there’s no gasoline leak then it’s got to be running poorly.
You haven’t supplied enough information even to get good wild guesses. Get it checked and fixed or park it.
CSA
At 5.5mpg you should be seeing the gas gauge go down as you drive any fair distance.
Are you sure someone isn’t siphoning out your gas?
Indeed - -someone like your son, who wants to drive the SUV and not the minivan? 
Forgetting about the gas issue for a moment, I think this car needs an inspection by a good mechanic in general. That level of rust could be a safety issue.
How do you figure you are getting 5.5 MPG?
an exhaust leak will cause crappy mileage due to the oxygen sensor readings being askew.
One thing that can cause a sudden drop in fuel mileage is a defective coolant temp sensor for the computer.
If this sensor has failed where it’s telling the computer the coolant temp never gets above -20 degrees, the engine will run very rich and never go into the closed loop mode. And this will cause the engine to use a lot of gas.
Tester
Why are you trying to avoid taking it to a mechanic? Do you have some sort of inspection issue? It sounds like you should.
It’s impossible for that engine to BURN 5.5 MPG worth of gasoline. Unburned gas has to be going somewhere. I’m cheap too, but that vehicle needs to be looked at by a shop. There’s a serious issue of safety involved here.
+1
Unless there is a leak, I think that it would be impossible for that 4-cylinder engine to get only 5.5 mpg.
If the rust on other areas of the car is really severe, it is very possible that rust has eaten holes in the fuel line. That type of leak could be deadly.
Thanks and sorry I haven’t gotten back on here sooner to read your comments. It does have an exhaust leak, but my mechanic has passed it for inspection year after year. I do, in fact, watch the gas guage drop as I drive. Finally getting it looked at this week and hopefully it will be as simple as a gas line. Just want to unload it and hoping to get at least $500 out of it. It has become a money pit but it has served well as a winter car. My Altima likes the comfort of the garage in bad weather.
Drive it the junkyard and see what you get.
Or be honest to the next person(karma).
Honestly, I’m sure the cause of the extreme fuel use can be found and corrected, but the rust has me concrened. I think Lion9car had a good suggestion. In addition to getting the fuel usage diagnosed, I strongly recommend a good going-over on the rack. If this vehicle is as rusted as it sounds, there are numerous places such as strut towers, control rod mounting points, suspension component mounting points, and even brake line fittings that should they fail could cause a serious crash.
Safety is your most important concern. Both a gas leak and excessive rust could be unsafe.
I too think it would be impossible for your van to get 5.5 MPG. My first car, a '74 Cadillac, with a 500 cid V8, managed to get at least 8 MPG, even though I floored it all the time.
Is the check engine light on? If so, what codes are present? Does it run decently except for the poor mileage?