Magnum Sucking Gas

[Lawndoc012]

Well it appears that now that I got all my issues fixed, my magnum seems to be sucking gas. I am running 20" wheels and only got 280 miles on my last tanks of gas. My driving habitats and travel roads have not changed. Other than checking my air pressure what else can I do to ensure the best preformance and gas mileage?

[MagNite]

More info please. Like how many miles you have on your Magnum? Always check the simple stuff first such as air filter, PVC valve, etc. Are you ready for a new set of spark plugs? Ever had a tune up?

[Lawndoc012]

Sorry I am around 90K. Still need to check my PVC valve like you recommended last week. I guess that I want I am looking for recommendations. Maybe I need new spark plugs and a tune up....

[Mics Mag]

In addition to above reply. 20" rims with what size of tire? There are tire size calculators you can use online to know if your over sized, but generally larger means heavier. It also means wider witch adds more road drag if you will and increases load on the engine. In addition larger diameter can mean its good to lower rpm on the hwy but puts you at a point between where 1st and 2nd gear might be from a stand still. City driving becomes less cost effective. But they do look very nice. http://www.1010tires.com/TireSizeCal...?action=submit

[Lawndoc012]

255/45/20. Couple of months ago, before I was having issues, I was around 300-320 miles per gallon. When I was getting 300-320 I was running my 20's.

[mikesmagrt]

might want to check tire diameter , if it's different than orig and you didn't have the computer changed it will throw your speedometer and odometer readings off .

[SKULLBOY]

Maybe I need new spark plugs and a tune up....

Plugs are good until 160,000 kms according to the service manual...........A plug change on the 3.5L is a big hassle as the upper intake manifold has to be removed to access the passenger side cylinder bank...........

[ToddStone]

If you get the tuner, you can check to see if you have any sensor issues. That and you can change the timing a bit with it to 89, 91 or 93 octane. If you go with the 89 octane tune and run 89 through it, that would help a bit. You might even want to run some fuel injector cleaner through the system, maybe check and see if your fuel filter needs to be changed.

Get some SeaFoam and read the instructions on how to use it. I've heard that it works really good, scary when you use it for the first time, but works really good.

[cleary524]

gasoline has been switched over to winter blend by the refineries = more ethanol (maybe?). I know typically this time of year my mileage with any vehicle I've ever owned goes down a little. Engine idles a little more in the morning, engine takes a little longer to warm up, tire pressure goes down to to atmospheric changes in seasons, etc.

But if your at 90K miles then maybe a tune up would be in order. It doesn't hurt to pull a couple of plugs and get an idea of how they look and if there's still some plug left, re-gap them?

Also, maybe some other small maintenance items, like new air filter, PCV valve, throttle body could use a cleaning, etc. All these little things add up. Heck I just did all my fluid changes (transmission, transfer case, and both differentials) and my mileage went up about 0.7 mpg's!!! I couldn't believe it!

[Lawndoc012]

Thank you everyone for the input. I will have to give these things a try.

[7186dodge]

was that in town hiway, if all in town thats not horrible ..

[-plotnik-]

one word that will help clean out the engine SEAFOAM. it helps clean and improve mileage !!!

[OLJustice]

You can remove the motor. That should help with mileage.

[bipto]

You can remove the motor. That should help with mileage.

Nice...

[Bryali]

As is already being said, you might be ready for a tune up. Out plugs are good for 100,000mi, which is the same 160K Km that Skullboy said. With the tune up, make sure and get all those minor things that may get overlooked like the PCV Valve, Air Filter (clean or replace), brake fluid, radiator coolant, etc. The Predator MIGHT get you some better mileage, but only if you can keep your foot off the skinny pedal. Also, don't forget to check your blinker fluid and drain/flush it if necessary, lol.