Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Pontiac > Grand Prix
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 04-19-2011, 03:16 AM   #1
gtpmaddi
AF Newbie
 
Join Date: Apr 2011
Location: Edmonton
Posts: 1
Thanks: 1
Thanked 0 Times in 0 Posts
1998 grand prix GTP 3.8L V6 supercharged, random misfire

1998 Grand Prix GTP supercharged. Random misfire on cylinder 3 seems to only happen when accelerating through 3000 RPM's... If the supercharger kicks in before it hits 3000 Rpm's then no misfire at all and full boost. If not, car engine seems to shake a little and the SES light flashes. When this happens the boost gauge shows full boost, but little occurs and car has basically no power when this misfire happens. Used a code reader and it confirmed random misfire cylinder 3 only as well as traction control being stuck off. When I tried to look for the issue under the hood, found that the belt has been a bit chewed up (but only in one section) and the silver coil packs ignition header is corroded (only the header connecting to cylinder 3). Any help or advice that could shed a light on this misfire's cause would be greatly appreciated !
gtpmaddi is offline   Reply With Quote
Old 04-19-2011, 11:37 AM   #2
GTP Dad
Pontiac Guy
 
Join Date: May 2004
Location: Penns Creek, Pennsylvania
Posts: 6,441
Thanks: 2
Thanked 82 Times in 78 Posts
Re: 1998 grand prix GTP 3.8L V6 supercharged, random misfire

Welcome to AF!!

There are several possible issues here. First, how long since the plug wires were changed? Second, because the fuel pump kicks into high when the supercharger kicks in and increases fuel pressure there may be a problem with the injector on that cylinder. I would also do a compression check on that particular cylinder to see if you have a valve issue. I hope this helps with pinpointing the problem. If not post again and we can try something else.
GTP Dad is offline   Reply With Quote
The Following User Says Thank You to GTP Dad For This Useful Post:
gtpmaddi (04-19-2011)
Old 04-19-2011, 09:16 PM   #3
olopezm
AF Enthusiast
 
olopezm's Avatar
 
Join Date: Jul 2005
Location: Irapuato, Mexico
Posts: 1,456
Thanks: 149
Thanked 85 Times in 83 Posts
Send a message via MSN to olopezm Send a message via Skype™ to olopezm
Re: 1998 grand prix GTP 3.8L V6 supercharged, random misfire

Plugs and wires is a good place to start. You mention the silver tip on the coil is corroded, that can cause the misfire too. Use a brass brush and give it a good clean, if the wires haven't been changed for a long time replace them too...

If the belt is chewed replace it too, it may be getting weak and a broken belt is something you don't want as it can happen while coasting and you might not notice it since you don't look at the instrument cluster all the time when you're driving...

Oscar.
__________________
1995 Lincoln Town Car 4.6 Signature
1997 Pontiac Grand Prix GT 3.8
2000 Ford Windstar SE 3.8
olopezm is offline   Reply With Quote
 
Similar Threads
Thread Thread Starter Forum Replies Last Post
98 Grand Prix Wont Start, need help ASAP! atdudonis Grand Prix 3 06-17-2010 09:57 AM
1998 Grand Prix GTP Nada price Supercharged borninabarn Grand Prix 1 12-22-2007 08:36 PM
Belt Installation 1997 Grand Prix GTP 3.8 litre supercharged engine agalsguy Grand Prix 1 06-24-2007 11:26 AM
1998 Grand Prix GTP Bolt-on Upgrades wms004 Grand Prix 27 01-18-2004 10:14 PM
F/S 1998 Grand Prix GTP Coupe MustGoFaster Grand Prix 2 08-23-2003 01:52 AM

Reply

POST REPLY TO THIS THREAD


Tags
grand , gtp , misfire , prix , random
Go Back   Automotive Forums .com Car Chat > Pontiac > Grand Prix

Thread Tools

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



All times are GMT -5. The time now is 12:57 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts