The least fuel-efficient car EVER posted here...

[robbie]

Hello,
I'm going to start this with my dilemma. I'm driving a 1991 Mercury Grand Marquis with a 5.0L V8, 150hp. It's got about 125,000 miles. Now, it'll get 26-27mpg on the highway. Not bad! HOWEVER....around town, where I mostly drive it, I have some major problems. 17mpg is normal, and 15 is definitely not unheard of.

I've read that on some cars, the intake is so restrictive that the car burns more fuel than is necessary. I have also read about Mustangs with the same basic engine components but upgraded to 250 or so horsepower getting 30mpg. Would a less restrictive intake do anything for me? Or should I just try it and see?

I'd get a more fuel-efficient car, but I'm 17 and can't afford one at the moment...and besides, I like the Merc and it's in great condition. I'm including a few pictures of it.






Now, being that I drive 15 miles each way to work via a construction zone, dumping the spare tire is probably out of the question, even in search of mileage. Any ideas (non-body-related...aero is not much of a problem, at least less than you may think) will be welcomed with open arms!

[Who]

I'm no automotive engineer but I can't see how opening up the intake passages would help. You want to be operating it with the intake flow kept minimal. I'd stick to basics. Pump up the tires. Learn to coast. Accelerate moderately in lower gears and learn when to lift-off to get into the next gear sooner. Try and keep it in top gear and once in top gear, accelerate slowly or read the road and use downhills for that. Go over hills like you're rising a bicycle - that is let the speed bleed like you only have a lawnmower engine and then recoup it on the other side.

[AndrewJ]

get a vacuum gauge, that will help you see how much fuel you're using.

[Whoops]

I totally understand the dillema. I'd get a glass jar and put a quarter in it everytime you have to drive the PIG. When you get $1000, go buy a used Honda Civic, stick, plain jane. Install a new timing belt and water pump and start saving some money.


The problem is that somehow FORD figured out a way to make an engine, drive train that gets horrific mileage, no matter what you do. I gave away a 1967 Ford pickup, with a brand new engine, because it got 11 mpg, cold, hot, loaded, empty, it did not matter. It just got 11 mpg, no matter what I did. I have an 89 Civic Wagon, which I have about $1000 tied up in. If I drive it reasonably, I get 35+ out of it. If I drive it hard, I get 30+ out of it. It costs $35 to fill it, now, but I can still drive 325 miles or so, before I go to the gas station.

With the car you have, you can't improve the mileage enough to recover the cost of anything spent to improve it's mileage. You need to lay out a plan to dispose of it, or you need to accept its lousy mileage as a price for owning it. One or the other?

The quarter deal works a lot faster than you'd think, seems hokey, give it a try.

[Lazarus]

Few thing you can try. Start by making sure the car is in good mechanical shape (plugs, filter, etc). Inflating your tires to max sidewall pressures for less rolling resistance. You can go with a grill block. They are cheap to make and easy to install that will help the engine warm up faster. Look at your route and see if you can find another way that does not have as many stop signs etc. If you have flexibility leave earlier or later sometimes 30 minutes to an hour can make all the difference in the world. Here's a thread on driving tips. As always the biggest improvement will be with driving techniques if you're not getting up to speed. Welcome to the site.

[SVOboy]

Welcome to the site! I was just a bit younger than you when I first got into this stuff, no I'm SO MUCH OLDER (19, ). Good to see you taking initiative though.

If it were me I would do the best with what I had while trying to save a dollar a day from lunch money or eating pizza on the weekends until that + selling the current car could get me a little civic, crx, or metro. Keep your ear to the ground, because every so often they go for almost nothing.

Welcome aboard.

[DifferentPointofView]

Hey, Your not the only one driving a honking vehicle there's us truck and SUV drivers too. If your like me, you just can't bear to sell the vehicle you fell in love with >.< if you get a geo, you could save gas by driving it, then use that money to fix up the Merc the way you want it, and use that for a cruiser. Once I get enough to buy a geo, I'm gonna drive that everyday, stop puttin the miles on the jeep, and use it for recreation. I found a geo for 650 yesterday, so you can def. find them cheap.

[jazzie604]

aha, you're still not worse than my car and if I want to, I can easily get 10-12 mpg if I drive stupid hard. Im trying right now to get this week above 20mpg, so heres to hoping.

by the way, those 5.0s were known for completely clogging to egr screen, which leads to some performance problems but really hurt gas mileage as well. Ask a good tech in your area, they should know what Im talking about. Its like a $10 part.

[DifferentPointofView]

for your Evo should easily get over 20mpg's. it's rated at about 25 highway (old EPA) right? It's a 2.0L w/ a turbo. If I can get about just about combined EPA for what it's OLD highway EPA is rated at w/ a 4.0L I6, you can do it with yours.

You don't even wanna know what I can do if I drive stupid hard, If I floor it to 60, Gas gauge goes down about 1/8th tank, and that's with 23 gallons

[LibbyMetro]

A big difference from the Mustang 5.0 to the grand marquis 5.0 is exhaust limitation, your diameter from the down pipes back to the muffler are considerably smaller than the mustangs 2.5 to 3 inch exhaust , next time you need a exhaust system replacement , think of a dual exhaust system , you can pick them up for around 200-250 through summit , or 300-400 through flowmaster, if you dont stand on it all the time you will notice around a 2-3 mpg improvement, also mustangs weigh a crap load less than the grand marquis you at about 3775 curb weight and the mustang is 2775