s2k-tilldeath

So on my drive to work my cel flashed maybe 5 or 6 times then stayed on. I couldn't feel anything different with the car as in response, or any weird noises. I pulled the codes and it's P1399 and P0304 which is a misfire on cylinder 4. After doing some research and having my friends dad take a look at it, he said first thing he would do is a new coil for cylinder 4, what do you guys think? I'm pretty much a noob when it has anything to do with the engine, I really only know how to change the oil, trans, and diff. Any suggestions would be helpful from anyone. Thanks.

#172CR

When were your spark plugs replaced last?

s2k-tilldeath

I've had the car for 1 year and I haven't replaced them or looked at them. 84k on the car. Probably time to change them then huh?

vtecb

Yes change them to start. Also you could have gotten bad fuel. That can cause it. I have had a miss fire on 2 cyl. At one time, cleared it then it and it was fine. The sensors are seem to be very quick to respond. Try running Lucas fuel treatment/ injector cleaner through it.

Sabre

and *if* the code comes back, swap the coil to another cylinder and see if it changes what bank the code is on.If it does, THEN you need a new coil.

SickShift

Yeah I replaced my plugs to fix my misfire too at about 69k.

tomsport

i had the same issue, and it was just fuel. like brian said, clean it with fuel system cleaner and give it good fuel, the problem will go away

s2k-tilldeath

Ok guys thank you, today I will put some fuel treatment and new gas in, then clear the code. If it comes back I will swap the coil with another one. Also before I touch the coil how does the order go? If I'm looking at the coils #1 would be the one closest to the front bumper and #4 would be the one closest to the dash, correct? I will report back after I do fuel treatment and new gas. Thanks guys.

SickShift

Yep you got it. Thats the firing order. So you'd wanna swap the coil closest to the firewall.. #4.. if you get to that point. Hopefully the gas treatment will help. I always have used chevron supreme cause I like the commercials with the talking cars of course. Oh and never get gas when you see a gas truck there filling the tanks of the gas station. I've heard thats bad.

s2k-tilldeath

That makes sense, because then you would be getting the bottom of the barrel gas instead of good new fresh gas. So an update here is that I used the supreme at shell it was either 91 or 93 octance I forgot already with some gas treatment. After I filled the car with treatment and gas I cleared the cel and I have driven about 10miles so far and no cel. About to drive 10 more miles today to work and back so I hope everything goes well.