LNF Subaru Sound when cold
 

This car has given me more headaches than I ever thought it would. Now my LNF sounds like a WRX when I first start it up and try to drive it. I'm getting P0301 and P0300 codes along with a flashing CEL when I attempt to drive it in this state, but the longer the car runs, the less Subaru-y it sounds, and it gets to the point where it's almost normal. I was thinking it has something to do with the valvetrain, but wouldn't my problem be constant if that were the case? I'm fairly confused by this one

Usually that sound is valve train related. Like a rocker arm busted or missing. Coukd be bad timing too. You misshift or money shift?

Nope, I just drive it normal for the most part with the occasional WOT pull once every few weeks or so. Hell, I only drive the car maybe twice a week, and it's normally short drives of 2-3 miles or less. It's the fact that it started running normal after a half hour or so that has me confused to hell and back. :confused:

How many miles and when was the last time you changed plugs?

Miles on car and how clean are your intake valves?

Not that it would be a solution for you, but I would get miss-fire codes P0300 and P0303 (cylinder 3) every once and a while, but not consistent. Switched to non ethanol fuel and the issue went away. Usually would happen on a cool morning or night and would have a Subi thump to it while it was miss-firing. Did not change anything other than fuel type. As stated earlier, check your plugs and coils to make sure they are still good as they are the cheapest route. Don't see it being a rocker arm or other valvetrain issue as that would be consistent and throw a lot more codes that a miss-fire.

It's been so cold as of late, my car needs a better tuner (not me), It runs fine after it's warmed up, but the idling is not good until it's about 100 degrees for the coolant.

I'm thinking about switching back to GMS1 until spring.