Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 6th, 2021. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

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)

Idle Speed Oscillates


Recommended Posts

I have a 1999 C2 Cab with 33K miles on it that has an idle oscillation problem. Only happens when warm and happens most but not all the time. The idle speed oscillates up and down between about 500 and 1200 rpms (with the A/C off). I have replaced the throttle position switch, replaced the idle speed control, and have cleaned the throttle body and none of these fixed or seemed to change the problem. Is there another very likely culprit I could try or should I buy a code reader and get some codes out if there are any? Would appreciate some additional help on this one. Thanks much!! Dwight

Link to comment
Share on other sites

  • Admin

If you have replaced the idle control valve and the throttle position sensor and cleaned the throttle body then you likely have an intake leak somewhere.

You are only going to see that with an OBD II tool that can show air flow and TRA and FRA. Still it might not hurt to look for any pending codes.

Link to comment
Share on other sites

IF you have eliminated other things like Loren syggested, take a look at the temperature sensor. There have been many sensors that have gone bad and will give you the same symptoms. The sensor is located on bottom of engine just below A/C compressor. Pull off the connector and try cleaning contacts. Also, rule out a computer glitch by rebooting the computer.

Edited by 1999Porsche911
Link to comment
Share on other sites

I'm sure I'm missing something that is going to be embarrasingly obvious, but I'm still going to ask.

How does one reboot the computer? Isn't this done each time the ignition is switched off?

Disconnect the negative battery cable for a few minutes and then reconnect. You will need to reenter your radio code. The engine will hunt for a while until it relearns the f/a mixture, but should settle down if the reboot corrected the problem.

Have you cleaned the MAF?

Edited by 1999Porsche911
Link to comment
Share on other sites

  • 2 weeks later...

On re-booting the computer, is it true that turning the key to the on position for at least 1 minute and then off for 10 seconds will also re-boot the computer? The workshop manual calls out that procedure for something I think it calls re-setting but I had thought (maybe mistakenly) that it meant re-booting. Can someone please clarify for me.

Also, once re-booted, about how long does it take to relearn everything so I know whether it fixed the idle problem.

thanks

Dwight

Link to comment
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.

×
×
  • 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.