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

[wriley4409]

At 125k miles you are overdue for changing the rear end lube. Replacing this with a good synthetic gear lube will make a measurable difference in mileage. (hypoid gear sets have lots of friction)

Motorcraft 5w30 synthetic blend oil (really cheap at Walmart) in the crankcase should help a little too.

If your cooling system fan doesn't have a clutch, then adding a fan clutch adds a little bit to your mileage. Of course you could always add an electric fan, but that is much more involved than simply adding a clutch fan setup.

I second setting the air pressure in your tires higher than the Ford recommendation. My personal vehicles are usually set 10% higher than the manufacturer's recommendation, but some people go even higher.


Good luck with your car!

Wayne

[malibuguy]

wow, i wish Malibu1 got 15mpg on the highway

try 11.8mpg average on premium, then you got problems, lol

[elhigh]

Try checking the tranny fluid - if it's old and cruddy, it isn't doing you any favors. Have a reputable shop do the job right - don't go to Jiffy Lube or some such, take it to a dealer.
The jury is out on Slick 50 for most folks, but I'm sold. I trust it. Do an oil change with Slick 50; 3000 miles later change to Mobil1.
Check your front alignment. In fact, you might want a thrust-angle alignment while you're at it - I see some of these older Fords doglegging down the highway, they're just scrubbing their mileage away.

Honestly, the car looks great. Sell it and drive something more appropriate. If it's doing as well on the highway as you say, then pawn it off on some ol' duffer who doesn't have a regular in-town commute anymore. The GMarq is about 50% more car than you're likely to need, though I don't know anything about you or your lifestyle. But for a young'un scooting back and forth to school and work, a GMarq is, well, kind of fuddy-duddy. Get yourself a good used Golf, or a Jetta. They weigh a lot less and you might get lucky and find one with a diesel.

[diesel_john]

its tough to beat a car that's paid for, pencil it out.
40+psi tire pressure, syn. lube in gear boxes, set base timing to 12 degrees, single exhaust, new filters, try with and without EGR(if its stuck open real bad for mpg) some respond and some don't, Vacuum gage, check brakes for drag, esp. e brake cables, straight alignment, you probably have a great rear axle ratio, best mileage is drive fast enough to just keep the Torque converter locked up, sir coast alot, drive like you have no brakes (look way ahead as far as you can see), shut off if long wait, small fan on dash much better than AC, intake and exhaust mods won't help unless something is bad, because your only using 20hp (right), neutral coast with engine idle, drive like who, vacuum gage, careful with a grill block can damage things under the hood, and last but not least,
add one item at a time.

[robbie]

As I've only got a few minutes, I'm going to post what I can before I have to take off.

First: I cannot sell the car for financial and other reasons. I can't get enough out of it to buy anything even remotely better; in St. Louis cars like this are worth $500-800.

EGR screen has been cleaned, found out that issue a year or two back.

I have considered a new exhaust; I'm looking for one off the '87-91 Crown Vic Police Interceptors from a junkyard or other inexpensive place.

Tranny fluid has been replaced. Planning on a full flush at some point. Alignment was fixed by the previous owner, but (lol) they did it with the steering wheel off-center So now, to go straight, the wheel's turned about five degrees left. I'm used to it, though, so not a big issue.

It does have a functioning fan clutch. That may be replaced whenever the radiator completely goes; I figure that if the radiator's going to be out, I might as well change the clutch there while I'm at it.

I'm not driving to and from school...I'm homeschooled, so all I really use this for is driving to work

Grill block is not in any way possible. I've got a leaky radiator, and it runs a tad hotter than I'd like anyway, though still far under red line.

There is no brake drag. The thing coasts for about ten miles when I let off the gas at 55mph. And yep, it's got a 2.73 rear axle(not-limited-slip). From my figures, the engine runs somewhere around 500rpm on the highway

I actually HAVE to drive it in Drive instead of Overdrive around town, as otherwise it shifts into overdrive by 30mph and runs the engine so slowly that it instantaneously stalls. No joke. Once I'm up around 50 or so though, I do shift it into OD.

Since I just noticed and read the post about driving techniques, it's at the end.

I do drive highway about 80% of my commute. I take the shortest route to the highway, and I get off about two hundred feet from my job. I drive smoothly, and only go fast enough to keep from being run over by the crazy 18-wheelers

[diesel_john]

robbie, sounds like you doing very well for 17. I couldn't think of a better car for a young driver. The open exhaust will not help mileage unless the cat is or muffler is plugged. Your are not putting much HP thur and it's made for 150. Your radiator is you primary concern. Check places like Advance Auto for a rad. around $200 is good. Sooner the better if the anti-freeze hasn't been changed. It doesn't sound like the transmission is working properly. Check if the kick down cable or rod is adjusted correctly. Some have this method and some do it electronically. Should not stall in automatic. However in slow traffic, you are correct in shifting into direct drive so that the converter can stay locked at the lower speed. Also check that the converter is unlocking when its suppose to. To save money learn all you can. Read my previous post carefully between every comma is different idea. Your car is capable of 20+ MPG. And we haven't even got to aero mods, but no need if your driving city. I wish I had your rear axle. Keep good records. Let us know how much each idea helps.

[DifferentPointofView]

Originally Posted by elhigh

Try checking the tranny fluid - if it's old and cruddy, it isn't doing you any favors. Have a reputable shop do the job right - don't go to Jiffy Lube or some such, take it to a dealer.
The jury is out on Slick 50 for most folks, but I'm sold. I trust it. Do an oil change with Slick 50; 3000 miles later change to Mobil1.
Check your front alignment. In fact, you might want a thrust-angle alignment while you're at it - I see some of these older Fords doglegging down the highway, they're just scrubbing their mileage away.

Honestly, the car looks great. Sell it and drive something more appropriate. If it's doing as well on the highway as you say, then pawn it off on some ol' duffer who doesn't have a regular in-town commute anymore. The GMarq is about 50% more car than you're likely to need, though I don't know anything about you or your lifestyle. But for a young'un scooting back and forth to school and work, a GMarq is, well, kind of fuddy-duddy. Get yourself a good used Golf, or a Jetta. They weigh a lot less and you might get lucky and find one with a diesel.

Why pay someone else to change your oil and tranny fluid . The money used for labor could buy a nice vaccum gauge or something. I know how ya feel about sellin' the car man. If it's paid off, why the heck sell the thing for not enough money to buy something else, pay monthly payments for a short while so you have something to drive, and have to start over from scratch fixing problems that you've already fixed on the last car.

Haynes makes excellent how-to books on stuff like tune-ups and replacing parts and such. Pick one up if you need some guidelines to do work. Very helpful.

As far as the tranny, did they make band adjustments and stuff when they changed it (fluid) last?

[Daox]

Welcome to the site. Try the links below for radiators. I haven't personally used them, but have heard good things about them. Looks like a reasonable $118 with shipping, not bad.

Radiator w/ AC

Radiator w/o AC

[robbie]

Originally Posted by diesel_john

robbie, sounds like you doing very well for 17. I couldn't think of a better car for a young driver. The open exhaust will not help mileage unless the cat is or muffler is plugged. Your are not putting much HP thur and it's made for 150. Your radiator is you primary concern. Check places like Advance Auto for a rad. around $200 is good. Sooner the better if the anti-freeze hasn't been changed. It doesn't sound like the transmission is working properly. Check if the kick down cable or rod is adjusted correctly. Some have this method and some do it electronically. Should not stall in automatic. However in slow traffic, you are correct in shifting into direct drive so that the converter can stay locked at the lower speed. Also check that the converter is unlocking when its suppose to. To save money learn all you can. Read my previous post carefully between every comma is different idea. Your car is capable of 20+ MPG. And we haven't even got to aero mods, but no need if your driving city. I wish I had your rear axle. Keep good records. Let us know how much each idea helps.

Radiator isn't leaking a ton right now, perhaps a quart a month. Since it's buried under a mound of stuff in my car, including electrical equipment and other things, and since I don't have a whole lot of experience with cooling systems, I'm going to have the local mechanic put it in. I know him pretty well, and he'll give me a good deal installing stuff that I already have.

I change my oil every 2,500 to 3,000 miles. At the moment using whatever the cheapest stuff Walmart has...after 15 years of non-synthetic, I'm not sure synthetics would do much good for the cost involved with filling it with them. It takes a LOT of coolant

Rear axle causes some issues in the rain--live axle, no limited-slip diff, and massive torque mean I drive sideways when it's wet! At least I'm getting good experience if I ever want to go dirt-track racing

Kick down cable is adjusted properly. I've gone over this car, replaced quite a few things that went bad or were just toast(two alternators, wiring harness(mechanic), brakes, tires, HVAC controls, patched rust in rear fender, various gaskets, hoses, belts). It may need head gaskets in a year or two due to coolant leakage, but it's low enough now that from the experienced people I've contacted, it's good for a while. Holds compression nicely. Only problem is that it hates St. Louis' summer "oxygenated gas"...runs extremely poorly due to lack of oxygen in the fuel. If I go out of town in the summer, I get 20mpg...on St. Louis gas, 15mpg It'll get close to 20 around town in fall and spring, if the temperature is above 40 and below 80. Unfortunately, that's about 5% of the year here

[diesel_john]

sounds good robbie, keep practicing your driving technics later