Boxster S Misfire

[Nicky English]

Hi All,

The CEL started flashing on my 04'Boxster S this morning and then developed a misfire. After driving a little further the fault went for several miles, then came back again. I've been told to have the Air flow meter changed then the spark plugs, does that sound like good advice ? aparently the fault codes showed a misfire on most cylinders (or at least 4 cyls I think). Im a new member, so thanks in advance to anyone taking the time to reply, much apreciated !!

[Frodo]

First things first: If it's a flashing CEL, you DON'T want to drive it, at least not very far at all.

Mine only flashed very briefly. I ended up taking it up to a place in Twinsburg, OH ("Steinel's Autowerks", a place I highly recommend from what I've heard and from what I've seen in person). He told me the misfire was brief (a few seconds) and that all kinds of harmless things could have caused it. He reset it (the CEL) and told me to run it hard driving home---blow any nasties out of the system.

I did so, and the CEL hasn't recurred, at least not so far. It is, and has throughout, always run fine.

My thread on the same issue: Flashing CEL

[Bladecutter]

Originally Posted by Nicky English

Hi All,

The CEL started flashing on my 04'Boxster S this morning and then developed a misfire. After driving a little further the fault went for several miles, then came back again. I've been told to have the Air flow meter changed then the spark plugs, does that sound like good advice ? aparently the fault codes showed a misfire on most cylinders (or at least 4 cyls I think). Im a new member, so thanks in advance to anyone taking the time to reply, much apreciated !!

Well, honestly, the first thing you should look at is "What was the last thing done to the car before the CEL came on?"

If you just had the spark plugs changed a couple weeks ago, then I start by pulling off the coil sticks, checking to make sure the spark plugs are properly torqued down, and then making sure the coil stick snap into place.

If the CEL comes on again after that, pull the codes, and let us know what they actually are.

BC.

[Boxtaboy]

I've read what Frodo says too... that if the CEL light is flashing, it's something that warrants you not driving the car anymore until you can get it looked at. If it is a solid light that doesn't go out, then you can continue driving it for a while, and get the codes read to see what the issue is.

You should get the code read (either buy a code reader at an autoparts store, or bring your car to a shop where they can be read). Once you get the codes, you can then determine what might be the problem. Good luck.

[ppbon]

Originally Posted by Nicky English

Hi All,

The CEL started flashing on my 04'Boxster S this morning and then developed a misfire. After driving a little further the fault went for several miles, then came back again. I've been told to have the Air flow meter changed then the spark plugs, does that sound like good advice ? aparently the fault codes showed a misfire on most cylinders (or at least 4 cyls I think). Im a new member, so thanks in advance to anyone taking the time to reply, much apreciated !!

That sounds like a disconnected coil pack.
The coil packs should click when properly connected and you should not be able to disconnect unless you press the sides of the connector.
If one of them comes off when you pull it, that's your answer.
Happy Boxstering,
Pedro

[Daniel R]

Go and have the codes read.

I have been through this process several weeks ago and made the mistake of self diagnosis. I replaced an MAF sensor that was in perfect working order and the problem was in fact the O2 sensors. The codes read misfires in 3 cylinders and faults in O2 sensors.

Just want to give you the heads up before you spend money on what may not be the problem. Pedro makes a good point to check the coil packs as this is a quick, easy and free check. If it fails to solve the problem get the codes read.

It is also worth mentioning something I read on a 911 forum. A member suggested unplugging the MAF sensor to see if this makes the CEL go away, and then work out if the MAFS is the problem. Sounds logical, problem is it DOES NOT WORK. I tried it, it got rid of the CEL so I bought a new one. As soon as the new one was in, back with the CEL. I can only guess that all the sensors work in unison or something of the likes.

Upshot is that there is no point in guessing what is wrong, at least not before reading the error codes.

Good luck.