04 GP GTP Hard Idle - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Pontiac When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Reply
 
 
 
Thread Tools Search this Thread
Old 04-28-2012, 10:34 AM   #1
Junior Member
Thread Starter
 
Join Date: Apr 2012
Location: Frankfurt, Germany
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
GTP in Germany is on a distinguished road
Default 04 GP GTP Hard Idle

Where to begin?
I'm getting a hard idle and throwing a P0300 code. She runs normal above idle with no acceleration delays. Occasionally I'll get the cat in danger blinking engine light. At idle on the scanner, cylinder 1 misfires on every cycle at idle and 3 misfires often.
I've replaced 'some' of the usual suspects; plugs, cables, mass airflow sensor, and fuel filter with no improvement. I'm thinking maybe a vacuum leak or a clogged cat?? ...but with no acceleration delays and no rotten egg smell, I'm leaning away from the cat being bad.
Without a smoking gun, it was suggested that I continue to replace the usual suspect parts by cost until the problem goes away. So, I'm thinking O2 sensors, coils, fuel pump and cat, in that order???
I'm in Germany with no Pontiac mechanics so my technical resources are limited...
Brian
GTP in Germany is offline   Reply With Quote
Old 04-28-2012, 12:19 PM   #2
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Thanks: 0
Thanked 16 Times in 13 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

P0300 is random misfire. Then with 1 and 3 showing up and you already changing plugs and wires. I would look at your coils. Make sure everything is clean under them. A vacuum leak should give you a P0171 code and make you run lean. I would still look around for one, but woudl still start with the coils.
Danthurs is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1999 GP GTP rough idle and acceleration Solid240 Pontiac 5 08-22-2012 09:20 AM
04 GTP supercharged randomly missing under hard acceleration sam72692 Pontiac 8 01-28-2012 01:57 PM
4T65E hard shifting when driven hard pontiacandryan 1992-1999 14 06-29-2009 05:25 PM
Ignition/fuel problem (hard start/stalls/rough idle) 1992 trofeo 1992-1999 43 04-02-2004 05:24 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:06 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.