Gas Mileage

1990 Grand Marquis Wagon, 302 Fuel Injected Engine.

I typically got 18 MPG in it on E10. I did get 22 on continual driving once.

I think if I ran it only on E0, with Amsoil Upper Cylinder Lubricant, I could break 20 or 21. If I added an Electric Engine Fan to it (and believe me, I don't want to do many mods to the car at all,) I'd probably get 22. Add a Water-Methanol Injection kit (which will probably never happen) and tune up the engine because the WMI kit adds extra cylinder cooling, and I'd likely get 25. Top it off with a block heater that I would use each time before starting the engine in summer, and I dunno, 25.5?

Not that I have much interest in making the car look anything but stock (rear wheel skirting that matches the woodgrain would be one of the only things I'd like,) but it is a little tempting in modern traffic to slightly soup up the engine while also increasing mileage. I don't think I drive it enough to warrant much of this, though; the only things I'm likely to do any time soon are the E0 fuel and Amsoil UCL additive.

 

Till I read your last paragraph, I kept thinking, How much driving do you do in this car? It’s a balance to what you do to enhance mileage versus cash outlay divided into miles driven. I would say my 302’s seem to deliver 20ish mpg, and for the joy of driving these cars I’ll let up 5mph on the expressway, and roll in and out of stops to try and juice the mileage up, but any modifications over $2-300 bucks is marginal for the driving I do.

 

Yup. There's things you can do that don't cost much, if any, money. Things like clean/gapped spark plugs, clean/correctly-routed wires, clean cap and rotor terminals, cleaned-out air filter, clean throttle plate, correctly inflated tires (35 PSI max should be run at 30 PSI, 44 PSI max at 36 PSI),
prudent driving habits, they all don't cost much if any money, but go a ways to maximizing MPGs.

 

That's why I'm so reluctant, it's not a common driver. I figure I might gap the spark plugs closer, and it would be nice to fix the rear brakes so they're not dragging so much. But I don't drive it much, I just want to have it a bit peppier because it's a little bit concerning how slow it accelerates.

If I just use E0 Gasoline and Amsoil UCL in the tank, and gap the spark plugs better, that might help enough. The plugs are about 0.050" wide now, and surely that's letting a few horses go out the door.

Maybe I'd put the tires up to 40 PSI cold instead of 35 cold, too.

 

If you honestly don't drive it much, you're saving gas that way, as opposed to driving it as a daily driver. How much gas you burn on average per month does depend on what you drive; when you aren't driving the Merc, what are you driving? If it's burning the majority of what you use in gas per month, then improving MPGs in the Merc becomes a moot point.

 

Sort of like getting rich, through saving money, quoting Henry Ford: “One doesen't get rich by what he earns, but by how much he doesen’t spend.”

 

Yeah, I'm more concerned with engine power in the Wagon right now than I am with fuel mileage.

Though I can't see that tossing in a block heater or two (if I can install two) would hurt. I added a 600w one on my Explorer, and while it doesn't make a gigantic difference, it's of some small amount of aid when first starting the car.

 

A block heater will save engine wear, offsetting your vehicle's overhead expenses. Especially, if you plan on keeping it for a long time and putting high milage on it

Just don't get caught. The fine levied for doing that can get better spent at the pump

 

If you want uprated power, then a set of Mustang heads with factory hipo cam and 19# injectors, a conversion to MAF, Mustang shorty headers on full dual exhaust and an A9P computer with proper harness modifications, will give you Mustang power, but in a 4000 pound car.

 

Here's someone selling the harness, computer and upper plenum, right in my neck of the woods:

https://www.facebook.com/marketplace/item/383866934208315/?ref=showcase_feed

 

The price seems within right, as long as the deal's legit

 

Then he'd need to find the heads, cam and headers, modify the exhaust.