OK, for me this worked for better mileage

[MINIHEMI46]

OK Guys, about 6 months ago I posted this and I guess you guys forgot about it or didn't care then so I'm post this again...... I've had my PT GT for almost 2 years now. It's an 03 stone white color and all stock and NO Stage 1. I have been getting in the Ocala Florida area, just driving around and into town and some freeway. My fuel mileage has ALWAYS been around 20 to 21 MPG faithfully. I have used Mobile 1 10/30 since it was new with still the same mileage, never have used anything different until NOW. This is what happen and I don't know why or care[:I], I changed oil about a month ago to the NEW Mobile 1 10/30 15,000 mile oil. Bought it at Walmart, 5 Qt's for $23.?. Put the same Fram tough guard oil filter and the same type driving and NOW I'M GETTING 24 MPG and it's been 3 tankfuls. Drive about 290 miles on 12 gals of high test fuel. But the point of this story is I'm getting 24 MPG and the same driving habits...... Now to bring you up to date after 6 months now of driving I'm still getting 24 MPG [?]so just a thought you guys might want to try it and see if you guys have the same happiness that I have had for the last 6 months, you can't lose anything but can gain a lot.....think about it[8)].

[sawdust123]

Thanks for the update.

Just curious, now that you use the new oil, have you changed your filter change interval? What interval are you using?

[MINIHEMI46]

I haven't changed the filter yet, it's been about 45 hundred miles since I changed oils. I go about 5 thousand and change it all. And the oil on the dipstick is about a half a quart low right now.

[coolvanillagt]

Having made 3 trips of 400 miles each these past 3 weekends, I've found that a best of 26 mpg is attainable only if I set the cruise at 76-78 and maintain it much as possible. This is with the a/c on, fairly flat terrain and tires at 34psi all around.
05 GT w/auto. and now 4700 miles. This weekend is the switch to Mobil 1.

[MichaelDay]

Coolvanillagt, Chrysler recommends the GT tires be run at a MINIMUM of 38 psi. I run mine at 41 psi. The 34 psi is for non GT's. Check the sticker on the drivers door. The GT uses high load rated tires that don't have adequate load handling at the lower tire pressures.

You should find your mileage somewhat improved by going up to 38-41 psi.

[SteelBlueGT]

I find I get better fas mileage (24 MPG) if I keep speeds down to 70 mph using cruise control and tires pumped up to 42 in front and 38 in back! It just is not fun so I keep it at 80 mph in the fast lane and get 22 mpg.[8)]

[bigtommy83]

Royal Purple did the same thing for me. Only i went from 19mpg to 25mpg. A few times at 28. My best was 31, but that was stock before mods.

[ElectricBlueGT]

My past two trips have averaged 30-31 MPG. I have an '03 GT with an AutoStick, Stage 1 and a plastic intake manifold. My two trips (each 360 miles minimum) were done at 70 MPH with cruise control. 360 and 378 miles, each on 12 gallons of gas.

Scott

[SteelBlueGT]

If I cold get 30 mph just once I would consider my car perfect and never sell it!! 24 mpg is my best going a constant 70 mph!

[Fodder4U]

Yep Royal Purple is the only oil for me. You gain a bit more power and get more milage. Can't beat it IMO.