Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)
Sign in to follow this  
63buglover

Intermittant Misfire

Recommended Posts

Good evening all...

I recently purchased a 1997 Boxster with 5 speed transmission, with 85k miles. I have an issue involving intermittent misfire condition. The misfires occur generally when the air temp is cooler; maybe < 75 deg.; doesn't seem any worse in rainy conditions. The code reader spouts out P0300 (Random multiple misfire), P0304 (Cylinder 4 misfire), P0305(Cylinder 5 misfire), P0306 (Cylinder 6 misfire). The seriousness of the issue differs; at its worst the CEL light flashes and the car has very little power. Generally, after the engines heats up, if I shut off the ignition and restart the car, the condition disappears. Most times when I leave work in the evening the car runs as poorly as it did that morning, but if I recycle the ignition, it runs fine. When its running seemingly OK, sometimes I will still get a very occasional, very short misfire in the higher RPM ranges.

The first O2 sensor on that bank was also defective when I purchased the car; I have replaced that already. The car definitely has a smoother power range, and more power after replacing the sensor (when its not misfiring).

I have seen some posts concerning cracked ignition coils; all six of my coil packs are cracked. It seems to me that moisture would make the misfires worse if it were due to the cracked coil packs. It also seems odd to me that all the cylinders on one side are showing the misfire, and none on the other bank.

Any suggestions? Thanks!

Share this post


Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

I for one would start with replacing the cracked coils.

You could swap the coils from cylinders 4-6 over to 1-3 and see if the misfires follow.

It is possible that the coils on the 4-6 side have seen more moisture or some of them are on their way out.

Here is the coil pack diagnosis flow chart if you want to diagnose the coil packs using multimeter/etc..

http://www.renntech.org/forums/topic/39226-any-reason-to-replace-coils-if-not-cracked/page__view__findpost__p__207346

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.