Runing rough at idle in P/N and on decel (11/14) - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 09-26-2007, 11:02 PM   #11
Senior Member
True Car Nut
 
Join Date: Jan 2005
Posts: 3,295
Thanks: 0
Thanked 0 Times in 0 Posts
MyLittleBlackBird is on a distinguished road
Default

Misfiring on all cylinders..... Damn Mike.... You've got a real brain buster here... There is no reason to suspect the MAF sensor itself, is there? What do the plugs say, if anything? No need to pull them all since you have a miss on all cylinders. I hate this guesswork crap. When misfiring in park/neutral, can you give it slight gas and have the misfires stop? I wish I could stand and look at it with you. It'* always nice to see things in person.
MyLittleBlackBird is offline   Reply With Quote
Old 09-26-2007, 11:38 PM   #12
Senior Member
True Car Nut
Thread Starter
 
95naSTA's Avatar
 
Join Date: Feb 2003
Location: Philly
Posts: 4,508
Thanks: 0
Thanked 0 Times in 0 Posts
95naSTA is on a distinguished road
Default

Quote:
Originally Posted by MyLittleBlackBird
Misfiring on all cylinders..... Damn Mike.... You've got a real brain buster here... There is no reason to suspect the MAF sensor itself, is there? What do the plugs say, if anything? No need to pull them all since you have a miss on all cylinders. I hate this guesswork crap. When misfiring in park/neutral, can you give it slight gas and have the misfires stop? I wish I could stand and look at it with you. It'* always nice to see things in person.
Well I've tried two MAFs already.
I haven't checked the plugs yet..
If I give it gas in P/N it smooths out but I don't remember if the scantool stops detecting misfires.. I'll check that out.
95naSTA is offline   Reply With Quote
Old 09-27-2007, 01:09 AM   #13
Senior Member
True Car Nut
 
Join Date: Jun 2004
Location: Glendale, AZ
Posts: 3,459
Thanks: 0
Thanked 1 Time in 1 Post
big_news_1 is on a distinguished road
Default

I guess I would suggest looking at the plugs, or at least the front bank. Check wire resistances, as you already mentioned. You basically need to go over that thing with a fine-toothed comb.

Check battery voltage and alternator output. Maybe there'* something wrong with the power being supplied to the ICM. Look into it if you haven't already. Cars do weird things when the voltage or amperage being supplied is erratic.
big_news_1 is offline   Reply With Quote
Old 09-27-2007, 08:10 AM   #14
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

Have you tried spraying the engine seals (Upper/lower etc) with TB or carb cleaner when it starts acting up to see if one of the gaskets may have gone?
BillBoost37 is offline   Reply With Quote
Old 09-27-2007, 10:20 AM   #15
Senior Member
True Car Nut
Thread Starter
 
95naSTA's Avatar
 
Join Date: Feb 2003
Location: Philly
Posts: 4,508
Thanks: 0
Thanked 0 Times in 0 Posts
95naSTA is on a distinguished road
Default

I sprayed those surfaces with the maf cleaner(alcohol) since it was the only thing I had on hand besides brake clean.
I'll stop by an autoparts store today or tomorrow and grab a can of carb/TB cleaner and try that.
95naSTA is offline   Reply With Quote
Old 09-27-2007, 10:44 AM   #16
DINOSAURUS BOOSTUS

Expert Gearhead
 
BillBoost37's Avatar
 
Join Date: Mar 2005
Location: Enfield, CT
Posts: 41,391
Thanks: 0
Thanked 0 Times in 0 Posts
BillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of lightBillBoost37 is a glorious beacon of light
Default

If you didn't notice anything with that..you probably won't with carb cleaner. Hmmm You've checked all the usual suspects.

Are you tuned for your TB and UIM?
BillBoost37 is offline   Reply With Quote
Old 09-27-2007, 11:11 AM   #17
Senior Member
True Car Nut
Thread Starter
 
95naSTA's Avatar
 
Join Date: Feb 2003
Location: Philly
Posts: 4,508
Thanks: 0
Thanked 0 Times in 0 Posts
95naSTA is on a distinguished road
Default

Quote:
Originally Posted by BillBoost37
If you didn't notice anything with that..you probably won't with carb cleaner. Hmmm You've checked all the usual suspects.

Are you tuned for your TB and UIM?
I was thinking that maybe the alki was evaporating before it could really do anything?

The prom is tuned for the TB and HVII. I'm getting steady MAF values and my fuel trims are good. I had both the TB and HVII in my last car and it ran without issue.

Another thing I haven't checked yet is the PCM harness ground thats near the oil pressure sending unit..

It'* so odd that I would hardly notice a problem driving if it'* cool out and theres no traffic..
Its got to be something closed loop and load related. In P/N theres no load and during decel there is no load. As soon as I'm stopped or almost stopped in D and the engine is working agianst the converter, there is no problem. As soon as I give it gas, theres no problem.
95naSTA is offline   Reply With Quote
Old 09-27-2007, 11:45 AM   #18
Member
Posts like a V-Tak
 
Join Date: Jun 2007
Location: Plymouth WI
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
lammers is on a distinguished road
Default

Have you tried replacing the ignition control module? it'* the piece the coils sit on. i remember a buick with a 3.8 my father was fixing, and whenever it got warm, the chip would heat soak, and the car would start misfiring and would die. just a thought of something that it could be.
lammers is offline   Reply With Quote
Old 09-27-2007, 11:49 AM   #19
Senior Member
True Car Nut
Thread Starter
 
95naSTA's Avatar
 
Join Date: Feb 2003
Location: Philly
Posts: 4,508
Thanks: 0
Thanked 0 Times in 0 Posts
95naSTA is on a distinguished road
Default

Quote:
Originally Posted by lammers
Have you tried replacing the ignition control module? it'* the piece the coils sit on.
Yep, swapped ICMs. (it'* in the long list up top)
95naSTA is offline   Reply With Quote
Old 09-27-2007, 12:08 PM   #20
Senior Member
True Car Nut
 
Join Date: Jun 2004
Location: Glendale, AZ
Posts: 3,459
Thanks: 0
Thanked 1 Time in 1 Post
big_news_1 is on a distinguished road
Default

I assume you already checked battery and alternator output? Worth a shot, I say.
big_news_1 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
engine not runing right bearsfaninwisc 2000-2005 11 06-11-2006 01:48 AM
rough idle and other things... SSEi95 1992-1999 16 10-04-2004 02:45 PM
From rough idle to high idle randman1 1992-1999 25 09-07-2004 09:20 PM
'00SSEi:rough idle,high idle...Please Help.... GTP2SSEi General GM Chat 2 07-29-2003 01:46 PM
Rough idle and SES Allmachtige 1992-1999 16 07-19-2003 09:57 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 04:37 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.