I was laid-up for two days and it rained very hard both days. When I went to start my 02 911 with 80K miles it ran rough and then set two codes. One was mutiple cyl misfiring and the other was no 5 cyl misfiring. Was it just wet or should I do something about sealing it, do I need new coils or can I just spray a water disperser on the coils like WD40 and see if it happens again. After a bit of driving it went away the check engine lamp went out and it runs fine. Any suggestions? Oh yes it has a Fabspeed intake with open K+N filter. if the filter got soaked being under the air intake grill could that cause the same problem and after it dried out the problem went away? Curious????

 

Your filter probably was soaked and was putting water into the motor. It has happened to me a few times.

 

Thanks J I was a little worried

 

Water as mentioned one of the pitfalls of this type of intake.

 

I suspected as much but wanted to see if others with this type intake also have this problem. You've answered my question. At least its not serious. Thanks Guys

 

Any CEL? If so, it's probably cracked coils. You can get away with a small crack for a little while, but as soon as you get a big rain and they get wet, you'll get misfires and a CEL. This is not uncommon for the 996.

 

Yes got a CEL and my diagnostic tool said multiple cyl misfires and another code said #5 cyl misfires. I will be thinking about replacing all the coils and plugs soon. After it dried out it ran perfect but they must be failing or as stated earlier the cold air intake got soaked and I ingested water in the intake stream puting out the flame from ignition however #5 continued to miss for a while making that coil suspect in my opinion.

 

I would also say cracked coil pack(s).

 

After this happened I decided to clean my Fabspeed air filter and re-oil it just as a precaution, it looked pretty dry. After cleaning and oiling it it rained all week here. Not one problem, no CEL, no misfiring so I am pretty sure it was water in the intake and the freshly oiled filter repelled any water dripping on it. It ran great every day after being soaked in heavy rain all week.

 

I think most of the water will evaporate while entering the hot intake.

 

I know this is an old post, but the exact thing happened with my 911. Just about the same miles also. It rained all day and I started mine and same 2 codes. I drove it, cleared the codes, then it ran fine. Did you ever pinpoint the problem? What did you end up doing?


QUOTE=caperss;3869396]Yes got a CEL and my diagnostic tool said multiple cyl misfires and another code said #5 cyl misfires. I will be thinking about replacing all the coils and plugs soon. After it dried out it ran perfect but they must be failing or as stated earlier the cold air intake got soaked and I ingested water in the intake stream puting out the flame from ignition however #5 continued to miss for a while making that coil suspect in my opinion.[/QUOTE]