Random Engine Misfires, causing CEL wouldnt pass Inspection

[rainierez]

I have done all that except the new cat. (can't afford it, and stopped caring)

The real fun is that I was clearing the CEL (which clears the ECU, fuel maps etc.) and it would always seem to happen within say 50 miles and then nothing. I would clear the light and again. So i stopped clearing it. (left it on) and it hasn't happened in months. Just a CEL on all the time but no shuttering or CEL blinking. or anything. So I've given up. 26ish mpg is fine by me and there doesn't seem to be an ongoing problem.

 

[Mixerdriver]

was the cel ever blinking

 

[Milou]

I've had a random misfire for at least 7 months now (it is still misfiring!). I've had my spark plugs and wires changed. Three different mechanics have tested my coil pack, they say it's working well. My catalytic converter is finished.

I had a new EGR valve put in 2 weeks ago, and I my car has misfired since! This has been an on going and difficult issue. At the moment my EGR valve is unplugged to test and see if it is the EGR valve that is causing the misfire. (there are no emission laws where I live). I was told that there would be no performance issues with my engine without it.
I feel empathize with your frustration! I hope that my issue will be fixed soon.

 

[MaxPower]

How did they test your coilpacks? Coil pack failure is an intermittent ("random") problem (if the coil packs completely failed, the engine would shut down) and will be hard to detect if the misfires are infrequent. Given that your catalytic converter is shot, I still bet your coil packs are toast. When the mechanics were testing them, the coilpacks probably behaved fine, but that doesn't mean they're ok.

Your best bet is to replace them and see if that solves the problem. They're cheap enough that it's cheaper to replace them and see if it solves the problem than to spend hundreds of dollars diagnosing other things. Keep in mind the coil packs in our cars are known to fail.

You should also look for cracks in the air intake. However, given that the misfire (probably) damaged the cat, it's unlikely the air intake caused it since a ripped air intake causes the engine to run lean, which spares the cat.

Since you replaced the EGR, assuming it was done correctly, it's not the problem.

I've had a random misfire for at least 7 months now (it is still misfiring!). I've had my spark plugs and wires changed. Three different mechanics have tested my coil pack, they say it's working well. My catalytic converter is finished.

I had a new EGR valve put in 2 weeks ago, and I my car has misfired since! This has been an on going and difficult issue. At the moment my EGR valve is unplugged to test and see if it is the EGR valve that is causing the misfire. (there are no emission laws where I live). I was told that there would be no performance issues with my engine without it.
I feel empathize with your frustration! I hope that my issue will be fixed soon.

 

[Mixerdriver]

God I felt like I was the only one having this problem. I have my p5 in the shop as wee speak for the same problem. I got the car a month ago and have only driven it twice (I got it to drive to work). both times I had problems. Blew the car I mean a hole the size of my fist out the side so I replaced it. Then the CE lights started coming and the shuttering. Into the shop and was told it was my coil pack. Replaced it and was told she was fine on the way home she stared shuttering differently. pulled the plugs and the gaps were all off regapped them and she drove fine for about 20 miles the The F Ing CE light came back on and shutter shutter so my wife dropped her off today. I'll let you know what it is know and when she comes back I'm driving with the CE light on if it comes back F it.

 

[rainierez]

So pretty much daily this was happening to me. And each time it happened I would check the code (laptop next to me) and then clear it. and it would come back within 50-75 miles. then one day I stopped clearing it and it stopped happening. (oh and my MPG went from 26 to 28-29 so bonus) Now i just leave the light on and there are never any shutters and it doesn't blink so F it I'm tired of worrying about it.