jrm87

Hi I am new to this forum and having a Porsche but this seems to be a great forum.
I am posting because I recently have had a misfiring problem with my 2000 911.
I first noticed an issue when it was up to temp at low rpm's. I got home and it threw codes p0301, p0303, and p0305. The car has about 78k and the 60k service was done on time replacing fuel filter and plugs and all that good stuff.
I haven't been driving the car. I just cleared the codes and fired it back up and it came back with p0301 only. It was misfiring kinda bad so I didn't take the time for it to warm up and have not driven it to see if other codes would pop up.
Any info would be greatly appreciated. I plan on taking it to the dealer Monday next week if I can't figure this out and fix it myself. Let me know if anyone has any suggestion's to help diagnose this.

Thanks for looking and any help!
Jesse

Barn996

Coil packs ever been replaced? Show us your Porsche pics so we can help you with your misfire, welcome to Rennlist.

Macster

Whenever I read about engine misbehaving appearing after the car has not been driven for awhile I think of rodents have been at teh car, at teh wiring.

(I was in a dealer the other day and came upon a car in for rodent damage. The check engine light was on. The code pointed to a problem with the gas tank vapor recovery/ventilation system. The tech removed the panels under the car that exposed the small tunnel that the coolant pipes run through and on top of one pipe is the vapor line that runs from the tank to the engine. The mice had gnawed through this line just enough to create a small air/vapor leak. In another case, some months back, another car was in with engine misbehavior (I do not know if the engine was misfiring) with check engine light on and the tech found in this case rats had been at/in the car and had gnawed the engine wiring harness which was causing the engine to misbehave.)

If you can find no signs of rodents -- check the top of the underneath plastic panels for rodent sign/nesting trash -- then the coils are suspect.

As is the quality/freshness (even the seasonal blend) of the gasoline in the gas tank.

Sincerely,

Macster.

jrm87

When I say the car hasn't been driven, I mean only a few days. Its driven just about daily, just not since the misfire. It just started the misfire about a couple of days ago. I was thinking the coil's as well. I just wasn't sure if that made sense because it said cylinder 1,3,and 5 where all misfiring. Is it common for more than one to go bad at a time? I will fill it up with gas and drive it around and see if I can get any other codes to pop up. As of now its just cylinder 1 since I erased the codes.
Also what kind of pics would be helpful? I have not taken anything apart as of yet.

jrm87

This is confusing. I just took out the car got it warmed up and topped off with gas. Got home and scanned it and now it says p0301 and p0304. Only misfiring at low rpms and idle. Any ideas?

C4CRNA

It is customary to post pictures of your car prior to asking for help.
Sorta introduces you to the community.
What part of the country are you in and do you keep the car in a garage or outside.

jrm87

Gotcha. The car has been in Florida the past year I've had it. Garaged most of the year but driven almost daily. I just moved to Kentucky last week. During my move when I drove it here, it rained the whole time. Im not sure if that has anything to do with the issues Im having now, I just figured Id mention it.

pesuazo

When I was searching for my cab, that is the color I was looking for....beautiful.

My money is in the coilpacks, specially since you mention the rain.

-P

C4CRNA

Rain can be a culprit! Thats why I asked.
Thanks for the pictures. Welcome!

logray

Here is the misfire troubleshooting guide:

http://www.renntech.org/forums/index...ttach_id=24613

Lots of good info in there, plus page 6 has the coil pack troubleshooting guide.

Misfires can be caused by a number of reasons, some of them will produce other DTCs (codes), and some will not.

jrm87

I just replaced all 6 coil packs and spark plugs and cleared the codes. I started it back up and the code 0301 came back immediately. Does it take a while for the ecu to recognize the change or should it be fixed instantly? I only had time to let it run for a couple of minutes but it was still missing.

fpena944

I have a similar problem that my mechanic is looking at but with me it is all in one bank and only misfires about 5k rpm. Coils check out, fuel injection looks good, timing looks good, spark plugs were just changed again, and MAF is new. So it's a head-scratcher for sure.

I'll keep you posted when I find out what the cause is.

dsowen

Not sure where you are in KY, but if you're in or near Louisville, I recommend Stuttgart Specialists as a good independent shop. My guess was the coil packs....

vange_c4s

i would have guessed coil packs/spark plugs too - but those are new. hmm.

i had a similar experience with my c4s. misfire cyl 3. right after spark plug replacement. i was lucky. the conector had worked its way loose (never put on properly...). i cleaned it, reconnected it and no problem.

keep us posted on your progress. good luck

vange_c4s

(coil pack connector)