Any ideas ... Misfire Cyl 1 and 3
 

Idle is a bit rough on 2001 S ... bops around 600-800 rpm at idle. I am encountering intermittent Solid CEL, flashing CEL, and nothing at all.

I am throwing P0300, P0301 and P0303 during solid and flashing CELs. I don't seem to be picking up anything when there is no CEL and I read. I once (and only once, out of around 10 reads) picked up a P1126 ... but this is cylinders 4-6, so I'm assuming its a red herring (maybe a slow o2 sensor???) and not related to the misfires on cyl 1 and 3.

I am thinking plugs or loose/cracked coils (wishful thinking?) ... my question is what else could be causing a cylinder 1 and 3 (but not cylinder 2) intermittent misfire?

These two cylinders seem to be misfiring in conjunction with each other (I've never read just a 0301 for example).

What else could this be? Any way a bad MAF or sensor could cause just a cylinder 1 and 3 misfire?

Thanks for all ideas.

ps. And not to be rude but in the interest of saving time, please please please no replies/allusions/witty narcissistic indulgences/ ironic statements / or indirect references to: the cosmic significance of flashing CELs, the need to immediately flat bed the car, the virtues of the dealer (or how much better the porsche reader is than obd), the importance of keeping your original cat after selling a p-car for sentimental reasons, nor the eternal damnation my soul will suffer if I do not immediately do any or all of the above.

how old are the spark plugs?

old.

Old as in I was already planning on replacing and they need to be replaced. Could be *really* old, I don't know when 1st owner changed.

OK, let's assume for a moment that they never got changed...
How many kilometres do you have on the car?
If it's more than - let's say - 60,000 it could well be worn spark plugs.
So why don't you start there?

One tip for changing spark plugs:
The electrical connectors which snap on the coils must really snap on and they are pretty hard to get all the way on (you MUST hear a click when you put them back on) otherwise you just introduced more misfire (ask me how I know ;)

new spark plugs fixed my miss-fire issues.

Hello sir,

I'm in Edmonton as well and just changed all my plugs a couple of days ago.. It's an easy job to get to them, I'd check the plugs / coils in the misfiring cylinders.. To jack up the car, pull the wheel and fender liner out and check the plugs takes no time. Cylinders 1 and 3 should be on the passenger side of the car first and last plug IIRC.

Cheers

Another edmonton boxster owner
depending which plugs u prefer
canadian tire carries bosch platinum and ngk platinum/iridium
$60 later & 1 hour I was done

Do one plug @ a time
make sure they snap in
check condition of wires
Clear codes and start again

C if O2 sensor codes come up again
if not...great
if they do. ....deal with it then
what fuel r u using?
fresh?
when was fuel filter last changed?
Somethings to ask yourself
Chris

You could also try rotating the coils to a different cylinder to see if the problem shows its sign on the other cylinder which would then tell you that you have a coil issue.

At the shop I used to work at anytime we had a bad running car we would check tune up things and if they were in question, then we would start there and it seemed like 90% of the time that would solve all of their problems.

any suggestions for where to get the CU plugs (bosch, beru, whatever) in town?

(I've read varying things about platinum/iridium in 986, and reccs to stay with OE copper. But I've also read about folks going platinum. Never read about experience with iridium??? Couldn't make a lot of sense out of it, mainly I was wondering about susceptibility to edmonton weather conditions?)

As for fuel, I was definitely wondering about this ... I am using mohawk 94 octane (which has 10% ethanol ... which could throw o2 sensors off I'm guessing), but am going to try out shell V power today.

Problem is definitely progressing/ getting worse.

I'm staying away from mohawk/husky 94
ethanol has its cons
when I was in montana
a lot of places were advertising premium without ethanol

I only fill up @ shell now
odd time @ esso

I'm running iridium no issues with plugs
going back to CU copper core would b a step backwards IMO

I ran a tank of 94 from husky & it t threw O2 codes
that's when I changed plugs

I like jake d 's idea if u have coil/wire problem
but I would do plugs 1st

Chris

Why would you change the type / spec of the spark plugs from what Porsche recommend - and pay a hefty premium for them to boot?
Running non spec plugs is worse than using the wrong oil - if it goes wrong, you can have serious problems !!

If you have a missfire & you don't know the history, go back to basics and change all 6 plugs to either Beru or Bosch as per Porsche recommendations. While you have the coils unplugged and on the bench, check visually for corrosion and cracking - if in doubt, replace.
If they look OK, swap the suspect coils with good ones from other bank, clear fault codes and start the car - if the fault codes follow the suspect coils then you have your answer....