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Low MPG, rebuilt heads

Old 09-03-2012, 01:01 PM
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Low MPG, rebuilt heads

Hey guys, I recently changed the head gaskets on my 92 v6 4runner and while in there replaced pretty much everything i could get my hands on. So after putting it back together, i've jumped from 11 mpg to 13.7
That is still a little too low from what im hearing and reading im supposed to get. I'm looking for upper teens closer to 16-17 mpg. The only thing i can think of (without having too much car knowledge, i repaired it with a family friend who is a mechanic) is that perhaps my exhaust has some issues since thats really the only part of the system that wasnt touched.

Any suggestions? The fuel filter was replaced, the air filter, oil filter, thermostat (dont think that makes a big difference.) and a few other odds and ends. Any help would be much appreciated.
Old 09-03-2012, 02:37 PM
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I'd say headers and cat delete could give you a little more. But there's your mileage and whether or not you have an automatic or a manual. And your driving style too.
Old 09-03-2012, 02:54 PM
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I rarely lay into it unless I have to. Generally I baby it. My first car was a junker that needs to be driven perfectly so that's how I drive normally. It's a 5 speed auto. Thanks for the info
Old 09-03-2012, 09:09 PM
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My suggestion would be first check the basics. Timing, what kind of vacuum is the engine pulling? Condition of plugs? O2 sensor reading rich or lean?
Old 09-03-2012, 09:19 PM
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general gas milage
test 02 sensor (will tell rich/lean)
test air flow meter
test tps
test egr flow
check for binding in steering
U-joints
check disengment of hubs
dragging brakes
synthetic fluids
compression test followed by cylinder leak test if needed
correct gearing for tire size
check spark advance
check for back pressure in exhaust
alignment will make a big difference
tire pressure
many times loss in fuel economy is not related to engine performance problems, dragging components are much more likley.
hope it helps
This is info from one of my previous posts, genaric.
Old 09-03-2012, 09:22 PM
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Also, sorry for so many posts, a cat delete will gain you absolutly nothing, exept more noise, unless your current cat is plugged. I.E. test back pressure, or physically look at the "honey comb" to see if it is compromised. Oh, not to mention more pollution and a raw gas smell for the guy tailgating you.

Last edited by mica; 09-04-2012 at 03:14 PM. Reason: Humor
Old 09-04-2012, 06:09 AM
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Originally Posted by Jaydork
It's a 5 speed auto. Thanks for the info
You sure about that?? Not trying to be rude or anything, but you either have a 5spd, or an auto, not both
Old 09-04-2012, 11:08 AM
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It's an auto, i say 5spd because, to my knowledge, they have 5 gears. So 5spd auto or 5spd manual. Oh well. Ill run through that list, thanks mica.
Old 09-04-2012, 03:11 PM
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Your auto is a three speed with an overdrive. Toyota definatly didn't put a four speed auto with an overdrive in a '92 runner. IIRC you look at the shifter it should say 1-2-drive then an overdrive button.
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