Every since ive changed just my muffler out ive had nothing but problems.

Right now my gas mileage is still at 22-23 mpg.

Mods

Denso Spark Plugs
K&N Filter
Comparable to stock muffler

If im not getting an SES light could I still be throwing codes. Next thing im thinking is my O2 sensor is not working.

I would never buy another lancer again with all these problems.

Can anyone shed some light.

 

what problems? wtf? you said problemS... with an S how about you shedding some light

 

if its not a huge pain, convert totally back to stock and see if the problem still exists. if it does then something went wrong. If it improves, its one of your mods thats doing it.

 

What was your gas mileage before the mods? Anyway, if you just got a muffler, I doubt that could cause anything unless someome somehow damaged the exhaust further up the line. As for the filter, that should be fine too unless it is installed backwards or otherwise improperly. And finally, I've heard about people having Denso (or any other iridium) spark plugs burn out quickly. Check to see if one of more of them are misfiring.

 

trying to picture a cone filter installed backwards....

 

gas mileage before was 25-26 mpg. The spark plugs are brand new and the filter only goes in one way. I even took out my subbox in the back and still no luck.

 

Im sorry problem.

Is that better.

 

Are you simply heavier on the gas now? It could also be the air filter, try putting the stock back in.

 

Who ever said anything about cone filter? All he said was K&N filter and K&N makes a replacement drop in box filter for the Lancer too, and I've seen a number of airheads put it in backwards and wonder why they couldn't get the box closed back up

 

Ive tried to turn the filters more way then one and it only goes in one way and my box closes with no problems.

Why would the air filter cause the problem if it is suppose to help.

Also if im not getting an SES light would my car still throw codes and show up on a code tester.

 

probly true. wanting to hear your muffler @ a higher RPM's perhaps?

 

just revert to as stock as possible and take it into the dealership bud. If you go back to as stock as possible and the problem goes away, then we can help you a lot more by narrowing down what the problem is. Not trying to be rude here, just letting you know why people are having a problem giving you advice.

 

Well the only thing I have left to put back to stock is the filter and everything else is pretty much stock now. Ive put on a comparable to stock muffler so no loud sounds so normal driving.

 

I don't think your computer would throw any codes without throwing the SES light. And yes, as long as the filter is all the way in, I can't imagine it causing any problems. Sure, it could be free flowing and cause changes in pressure, but I doubt anything noticeable. As long as you don't hear any noises or feel any vibrations, I would recommend doing nothing and continue to check your mpg and see if maybe you're just having a bad week. It could just be thinner air or the weather causing some differences in performance. Or more frequent use of the AC.

 

It has been about 2 months.