Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Post Reply
 
LinkBack Thread Tools Display Modes
Old 11-19-2017, 01:38 PM   #1
Registered User
 
Join Date: Nov 2017
Location: California
Posts: 11
DTC Codes P0300, P0305, P0306, P0304

My 2001 Boxster is making me nuts. Recent engine work:

- Replaced AOS
- Replaced MAF
- Replaced all four oxygen sensors
- Replaced coolant reservoir and all hoses
- Cleaned throttle body and intake plenum

Car is running rough at idle and showing CEL with DTC Codes P0300, P0305, P0306, P0304 (see attached image).



Any thoughts on what could be causing this?

Thank you!!!

mforester is offline   Reply With Quote
Old 11-19-2017, 02:25 PM   #2
Registered User
 
Join Date: Sep 2008
Location: Florida
Posts: 2,492
300 is a general misfire (most likely caused by the other codes).

The codes are all for cylinders on the same side. Have you replaced spark plugs or disconnected coil packs?

I'd look at the coil connectors and make sure all are connected to the correct cylinders and seated all the way. Sometimes its hard to tell if coil pack connector is completely seated. there should be an audible click.
dghii is offline   Reply With Quote
Old 11-19-2017, 03:18 PM   #3
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
First buy a "Super-Met-Al" paint pen.
Then mark the Bank 1 coil connectors in the correct cylinder sequence. You have no Bank 1 codes right?
Then disconnect the coil connectors on Bank 2 and figure out the correct sequence.
When you get the cylinder sequence right, the engine will run sweetly but may produce clouds of white smoke- caused raw gas from the misfire in the headers/cats. This is potentially dangerous for obvious(I hope) reasons. When the smoke clears (or the flames die down) , Mark the correct cylinder # on (the charred remains of ?) each coil connector
Someone over on Renntech recently did a long Post on this issue and gave all the fumbling errors and diagnostics.
Gelbster is offline   Reply With Quote
Old 11-19-2017, 03:24 PM   #4
Registered User
 
Join Date: Nov 2017
Location: California
Posts: 11
I've not changed the plugs or messed with the coils. I did have a shop replace the coolant reservoir and lines so perhaps they messed this up as it was running smoothly before I took it in.
mforester is offline   Reply With Quote
Old 11-19-2017, 03:30 PM   #5
Registered User
 
Join Date: May 2014
Location: S.California
Posts: 2,027
O.K. vacuum leak on Bank 1
Gelbster is offline   Reply With Quote
Old 11-19-2017, 06:41 PM   #6
Registered User
 
Join Date: Sep 2008
Location: Florida
Posts: 2,492
Quote:
Originally Posted by Gelbster View Post
O.K. vacuum leak on Bank 1
+1 As you have not messed with spark plugs.

dghii is offline   Reply With Quote
Post Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 02:37 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page