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gas mileage

Hmmm... Well, I'm on brand spanking new iridum plugs, wires, air filter, fuel filter, O2 sensor, MAP sensor, IAC controller, PCV and EGR valves, intake manifold gasket, exhaust gasket, supercharger gasket... (not to mention 5,000 mile old Michelins all around on a recent balance and rotation). You'd think I'd be getting better than 24.x. Though I'm still getting the Check Engine Light every time I touch the car and maybe the MAF is suspect, since I'm running out of candidates. Would that be having a big impact on fuel economy?
 


Question for anybody...I'm in Ohio. Does running 89 fuel vs. 93 fuel make a difference in fuel economy. I'm still running around 18 to 19 mpg on completely stock. Thanks in advance.
 
You would probably never notice the increase.. But it could save your Pistons so that alone makes it worth it.


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I think he was asking about a GT? If it is supercharged, it is much safer to run 93 than it is to run 87 or 89. In a GT, (Naturally Aspirated, except for the non-fleet 2006 - 2007 GT's that came supercharged), I'd just run the 87 or 89 since the higher octane won't matter as much in a N/A engine
 
tomtom123 said:
What code do you get? And yes, MAF affects fuel mileage, along with other things
Click to expand...

The most evil code of them all; P0171

A thought too - whenever I start the car I get a very audible clacking sound from the engine bay which I have always assumed was just the lifters. But Lucas hasn't quieted the problem even a bit. It always goes away after a bit of driving but it is definitely affected by any level of acceleration until it does.

Could I be looking at an injector problem?
 
Unplugged it and it ran normally for a few seconds until it the engine started to sputter.

Edit: Code didn't go anywhere.
 
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29.2 is the highest I have gotten so far... this is very little city and almost all highway. Premium 93 or 91 octane gas. So far I am happy with it.
 
i run 87 in my car, still get 35 on the highway if i drive it right. then one morning warmup its back to 20s, until you reset it going down the highway.
 
My stock white gtp gets about 17-18 city driving civilized and i don't know what it gets on the highway because I have yet to drive it on the highway.

My rusty blue gtp is rock solid at 19 mpg all city with me constantly beating on it (has a 3.5 and headers/needs retuned) and last time I had it on the highway (few years ago when I got rid of it) it would get 31 mpg all day long and 35 mpg without the hood
 
MY average MPG in my 2000 GTP is 28 on the highway with cruise control on at 80. In the city I get about what you stated.
 


my gas mileage (95 octane) is rated at 24-25 mpg in the city, on the Highway(Autobahn) between 15-17 mpg Dia higher at the highest speed.

ok speed limit? Is sealed off at 110 miles, :auto1:
 
Pontiac GP said:
my gas mileage (95 octane) is rated at 24-25 mpg in the city, on the highway between 15-17 mpg Dia higher at the highest speed.

ok speed limit? Is sealed off at 110 miles, :auto1:
Click to expand...
That sounds kinda backward but maybe I read it wrong. I'm just trying to figure out for the life of me how to get some better fuel economy out of this thing. I'm not complaining too much though because it's getting the same if not better than my old 2002 S-10 LS 4-cyl.
 
1BadGT said:
That sounds kinda backward but maybe I read it wrong. I'm just trying to figure out for the life of me how to get some better fuel economy out of this thing. I'm not complaining too much though because it's getting the same if not better than my old 2002 S-10 LS 4-cyl.
Click to expand...

:th_sign-oops:sorry
read incorrectly
 
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