As anyone has noticed I have had a very dramatic decrease in gas mileage from 25 to 22 mpg. The only mod I did was put on a aftermarket flowmaster muffler and put in diamond shamrock gas. After this my gas mileage decreased. Since ive changed spark plugs, air filter and went back to stock muffler but nothing has helped out the situation.

So would I have a valid reason to take it in for service and whatever the problem is should be fixed under warranty.

 

The "whatever the problem is" part is generic, and the dealership won't be as such. So, get prepared to know what coverage your warranty has and hopefully the problem will be covered...

 

I have bumper to bumper coverage for 36000 or 3 years. So all should be covered.

 

be prepared for them to take a stab at you about your flowmaster. We all know Mitsu dealers... "If they can... They will!" hopefully they wont be *** hats!

 

I dont have the flowmaster on there anymore. I changed it out to a comparable to stock muffler.

 

I think they're just warning you to prepare for a fight. Playing devil's advocate, it's "comparable" but not the exact one it came with, so Mitsubishi is not liable for any complications that are caused by the muffler or its installation. But keep in mind this argument (very important so listen carefully) they have to PROVE that the non stock part caused the problem. Now on to your second problem, we still don't know what's wrong with it. Playing devil's advocate again, I could just say your driving habits have changed enough to drop the mileage. Just my opinion, but I would get an outside mechanic to look it over and identify the real problem, pay him the $70 or whatever for the inspection, then tell Mistubishi exactly what was diagnosed and demand that they fix it under warranty.

 

did you check tire pressure... that can kill your mpg

 

don't ever think about getting an evo then...

 

The driving habit thing has been beaten to death. I drive and never go over 3000 rpm most of the time it is between 2000-2500 so driving habit is actually under or about normal.

 

How many threads do we need about this?

Personally, I don't even lose sleep over a 3 mpg difference. But if you care so much, then be done with it. Don't start 87 threads.

 

david, its that big heavy lug of a speakerbox in your trunk. Get a fiberglass mold made.

 

Guess you dont care about money. 3 mpg adds up tank after tank.

 

I took that speakerbox out as well.

 

As someone said this does add up and I dont have 87 threads about taking it in for service.

 

Yes but with an evo I would expect my gas mileage to be low. But when you put on mods that should help your gas mileage and it takes away something does not make sense.