Recently I've been getting 12.9 MPG in my 2.5rs, it's completely stock exept for the K&N Panel Filter, I get a CEL for my knock sensor, it comes and goes, could this be the problem? or maybe my o2 sensors are going?

 

when you get a CEL if I'm not mistaken it triggers a safe mode tune which could cause the decrease in mileage. But that's an extreme drop.

I'd guess that you have an issue that needs fixing.

 

Clean your air filter, blast the MAF with maf cleaner, reset ecu.

 

I cleaned the air filter, put injector cleaner, reset the ecu, new pcv valve, new spark plugs, and changed the oil and 00 2.5rs use MAP

 

wow man hummer status =/

 

I get the same mileage as my moms expedition lol

 

Dude, no RS should ever get mileage that low.

Get the knock sensor replaced and the front 02 sensor.

Both have huge effect on timing and fuel, and my guess is that your timing is severely retarded at this point, and you are just waisting fuel in a super rich mixture.

 

Yeah, my brother scoobiesnacks, you may know him (orlando) gave me my RS and he was avging 335 mpg

 

I'm having my dad bring a timing light to check the timing today also

 

Clean the MAF. It's really easy (I did 2 in about 20min) and cheap to do. It may or may not solve your problem, but it's worth a shot.
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Yamaha Rhino Specifications

 

There is no MAF on MY00 RS's. They are MAP

 

WTF!?!


You're Orlando's brother!

Damn, I haven't talked to him in ages. How is he doing? Did he grow any taller

 

oh, and you mean 335 miles per tank right?

You're brother's a mechanic, have him fix that ****

 

Yeah, I'm his younger brother haha, I just talked to him on the phone right now, he's doing good, getting his wrx finished up at GST...and nope it doesn't say much when your younger brother is as tall or taller than you :P

 

oh yeah sorry miles per TANK ahaha, my dads a mechanic I'll have him look at it, he's gonna check the timing once he gets home