Several months ago, I bought a 2002 Outback Sport with ~98k miles. Around 105k, the exhaust rusted out and broke at the muffler (damn PA winters). Rather than spending $130 on the OEM replacement muffler only, I bought a cat back exhaust off of an 02 WRX with 30k miles from a guy for $40, and I paid my mechanic $90 to install it (which had to be welded because the flanges didn’t line up correctly, and the size jumped from 2” to 2.5” at the flange).
Since I was increasing the size of the exhaust, I also decided to do a cheap mod to the intake that I saw on rs25.com. Basically, I removed the stock intake back to the elbow on the airbox and installed a Ganzflow style intake tube made for a 94 accord, which fits almost perfectly. I also bought a drop-in K&N filter that is installed in the factory airbox.
After all this, I definitely notice some more low-end power (not to mention the nice gurgle from the exhaust). However, every once in a while, it feels like the engine misfires. It happens most often when 1) I am going moderately slow at low RPMs (1000 to 1500) and then hit the gas suddenly or 2) when I just punch it. It doesn’t do it all the time. Sometimes it just takes off no problem. But other times, it hesitates and sputters a few times before taking off. It will also sputter periodically somewhat as I continue to accelerate with the pedal to the floor. I did notice that it doesn’t do this if I run higher octane fuel (89+).
I know just enough about cars to make me dangerous, but not enough to know exactly what to do here. I have some ideas based on what I can see. Should I change the fuel mixture? More rich? Less rich? How do I do that? How much should it cost? Is it something as simple as changing the spark plug gap or buying different plugs altogether? I’m trying to figure out if there’s something that I can do to fix the problem without the need to run premium fuel.
Any help is appreciated.
Since I was increasing the size of the exhaust, I also decided to do a cheap mod to the intake that I saw on rs25.com. Basically, I removed the stock intake back to the elbow on the airbox and installed a Ganzflow style intake tube made for a 94 accord, which fits almost perfectly. I also bought a drop-in K&N filter that is installed in the factory airbox.
After all this, I definitely notice some more low-end power (not to mention the nice gurgle from the exhaust). However, every once in a while, it feels like the engine misfires. It happens most often when 1) I am going moderately slow at low RPMs (1000 to 1500) and then hit the gas suddenly or 2) when I just punch it. It doesn’t do it all the time. Sometimes it just takes off no problem. But other times, it hesitates and sputters a few times before taking off. It will also sputter periodically somewhat as I continue to accelerate with the pedal to the floor. I did notice that it doesn’t do this if I run higher octane fuel (89+).
I know just enough about cars to make me dangerous, but not enough to know exactly what to do here. I have some ideas based on what I can see. Should I change the fuel mixture? More rich? Less rich? How do I do that? How much should it cost? Is it something as simple as changing the spark plug gap or buying different plugs altogether? I’m trying to figure out if there’s something that I can do to fix the problem without the need to run premium fuel.
Any help is appreciated.
