JohnnyXmas

Hey all, I've got an 04 Lancer ES here. The only things under the hood that are non-stock are the K&N intake system, new battery (precautionary) and Pulstar spark plugs. Both of these were added over six months ago, and I haven't had any problems with the vehicle in the 5 years I've owned it (until now). A few days ago, Chicago hit 20 below. I had difficulty starting the car initially, but that's to be expected. I let it warm up for about 15 minutes, and drove it for about 3 miles, and hit a problem. I gunned it coming out of a turn, and it stuttered a few times, and hung around 4000 RPMs without accelerating, and the check engine light came on. I let off the gas, and the car seemed to be OK. I drove the 15 mile trip to work, and had someone read the OBD code. The code is P0300, which means random misfires. I reset the computer, and drove the car down side streets home, with no issues. A few days later, the weather was much warmer, and I took the car on the highway, after the engine was thoroughly warmed up. I drove it pretty hard up to 60 mph, and the trans was going through the gear as normal, no hiccups or anything, and I regularly topped 4500 RPMs (automatic trans) through all the gears. The problem came then, around 60 MPH. Whenever I give it a lot of gas, I can feel the misfires, and the car hangs around 4000 RPMs. If I go easy on the gas, the car accelerates as normal, no misfires or anything. I've searched the forums and found some information regarding the problem code, but I don't want to go through a lot of the replacements steps, especially since some of them don't make sense given the situation (I doubt all 4 spark plugs are bad, etc). I'm looking for any advice or ideas any of you may have. Thanks in advance. . . -Jx-

4g94T

iTrader: (18)

You may have a clogged or bad injector(s)

JohnnyXmas

Yeah, I did think of that. I just don't have the resources to be buying random parts to see if they fix the problem. I only put mid to high-grade name-brand gas in the thing, and I ran a tank through it with some injector cleaner, but saw absolutely no difference.

oneonlywgs

iTrader: (2)

When I pop the p0300 code, I change the spark plugs. It depends what kind u are running. I run ngk's and change them every 3 oil changes.

I would check the spark plugs and spark plug wires.

Walkingchaos

iTrader: (25)

its the plugs and theres no point in running anything other then 87 octane fuel in that car with those mods. Between the hotter plug and the higher octane im not suprised your having misfire issues. Toss some cheap NGK coppers in there and see if it fixes the issue.

JohnnyXmas

Totally true (I fixed the problem) I run the higher octane gas in there out of pure superstition of "dirty" gas. i have no means of justifying that, other than I messed up injectors on two diff cars from cheap-o Citgo gas. The plugs WERE the problem, though not for what you're saying. I had a new tech at the shop install them cuz it's a new tech thing to do. Oil changes and spark plug swaps and whatnot. Simple stuff, right? I had the car at the shop today, so I took a look at the plugs. They were gapped a full .01" too wide, which put them about .011" beyond Mitsu and Pulstar spec. On top of that, one of them was cracked, and the other one on that coil was pretty fouled up. Can't say if the kid cracked it putting it in, or if it happened on its own (unlikely), but there it is. Maybe he cocked it and put a hairline fracture in it, and it cracked later, which is why everything ran fine for so long. Threw some NGJ iridium's in I had in the shop, and it runs smooth now. Thanks for the assist, sorry for cluttering up the forum. -Jx