p0300 Random/mult cylinder misfire (fixed) - 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 04-28-2011, 10:15 PM   #11
Senior Member

True Car Nut
 
sseidriver97's Avatar
 
Join Date: Mar 2010
Location: Portage mi
Posts: 7,124
Thanked 3 Times in 3 Posts
sseidriver97 is on a distinguished road
Default

Thread moved to proper section
sseidriver97 is offline   Reply With Quote
Old 04-29-2011, 11:57 PM   #12
Member
Posts like a V-Tak
Thread Starter
 
bonnie_99's Avatar
 
Join Date: Feb 2011
Location: Michigan
Posts: 42
Thanked 0 Times in 0 Posts
bonnie_99 is on a distinguished road
Default

Hey gang,

Dan, 2K4GU, and anyone else who chimed in with awesome advice. I switched out the ICM and it purs like a kitten. By the way, I hope you don't mind I borrowed the monniker, "3.8 liters of twisted steel and sex appeal."

Thanks so much for your help.

Joe
bonnie_99 is offline   Reply With Quote
Old 04-30-2011, 12:06 AM   #13
Senior Member

True Car Nut
 
sseidriver97's Avatar
 
Join Date: Mar 2010
Location: Portage mi
Posts: 7,124
Thanked 3 Times in 3 Posts
sseidriver97 is on a distinguished road
Default

Glad you got er fixed and up and running
sseidriver97 is offline   Reply With Quote
Old 04-30-2011, 12:07 AM   #14
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

Good to hear you got it.
Danthurs is offline   Reply With Quote
Old 05-02-2011, 06:28 PM   #15
Member
Posts like a V-Tak
Thread Starter
 
bonnie_99's Avatar
 
Join Date: Feb 2011
Location: Michigan
Posts: 42
Thanked 0 Times in 0 Posts
bonnie_99 is on a distinguished road
Default

Hey guys,

Got another check engine light on 99 bonneville. P0300- random/multiple misfire and P0133- O2 Sensor Circuit Slow Response Bank 1 Sensor 1. No vaccum leaks, fuel injectors are working, coils are good, got good spark, new wires and plugs.

When I check the voltage on O2 sensor I get a normal reading of about 450 millivolts out of one of the prongs on the O2 sensor connector but no fluctuation on the other three. Should get a reading from the other prongs. Could the misfire and the O2 sensor be related. Is there more than two O2 sensors? I have been checking the one in the exhaust manifold before the converter.

Help,

Joe
bonnie_99 is offline   Reply With Quote
Old 05-02-2011, 06:58 PM   #16
Member
Posts like a V-Tak
Thread Starter
 
bonnie_99's Avatar
 
Join Date: Feb 2011
Location: Michigan
Posts: 42
Thanked 0 Times in 0 Posts
bonnie_99 is on a distinguished road
Default

Hey guys,

Got another check engine light on 99 bonneville. P0300- random/multiple misfire and P0133- O2 Sensor Circuit Slow Response Bank 1 Sensor 1. No vaccum leaks, fuel injectors are working, coils are good, got good spark, new wires and plugs.

When I check the voltage on O2 sensor I get a normal reading of about 450 millivolts out of one of the prongs on the O2 sensor connector but no fluctuation on the other three. Should get a reading from the other prongs. Could the misfire and the O2 sensor be related. Is there more than two O2 sensors? I have been checking the one in the exhaust manifold before the converter.

Help,

Joe
bonnie_99 is offline   Reply With Quote
Old 05-08-2011, 10:55 PM   #17
Senior Member
Posts like a Northstar
 
charliemax's Avatar
 
Join Date: Jan 2006
Location: Valley Forge, PA
Posts: 598
Thanks: 0
Thanked 0 Times in 0 Posts
charliemax is on a distinguished road
Default

Quote:
Originally Posted by bonnie_99 View Post
Hey guys,

Got another check engine light on 99 bonneville. P0300- random/multiple misfire and P0133- O2 Sensor Circuit Slow Response Bank 1 Sensor 1. No vaccum leaks, fuel injectors are working, coils are good, got good spark, new wires and plugs.

When I check the voltage on O2 sensor I get a normal reading of about 450 millivolts out of one of the prongs on the O2 sensor connector but no fluctuation on the other three. Should get a reading from the other prongs. Could the misfire and the O2 sensor be related. Is there more than two O2 sensors? I have been checking the one in the exhaust manifold before the converter.
You have the right O2 sensor. Problems with the back O2 sensor occur about once for every 500 front sensor problems.

With those check messages, you have a chicken and egg situation. Let'* check the bigee first. The O2 sensor is talking directly to the PCM, and the PCM has to hustle like crazy to manage your fuel trims and ign advance.

If you know what codes you have, you must have a scantool. The simplest, crappy one will do. Use it to read the O2 sensor while the car is running.

A good reading from an O2 sensor is one which toggles up and down at sub-second speed. It'* indicating a rich burn cycle, and a lean burn cycle.

The reading should jump (I forget if it'* a whole number or decimal) from around 1 or 2, to around 8 or 9. Back and forth, extremely fast. So fast, you can barely catch the reading at either end.

If it'* just moving from say, 4 to 7, or it'* real sluggish... you are likely to have a sick O2 Sensor. When was the last time you replaced the O2 Sensor?

FWIW, our cars run in a continual state of a rich and lean burn for emissions purposes. There are 2 groups of gases which the cat has to scrub. It needs a rich burn to scrub one and a lean burn for the other. We don't even notice this shifting during operation, it is so minor and so fast.

But it is crucial to the proper operation of the engine. If the O2 sensor is skrewered, it'* sending bad info to the PCM, and the PCM is doing all kinds whacky stuff to fuel, air, and spark to try to get it back to proper ranges.

Make sure your contacts are clean on the O2 connector, and don't let the connector touch a plug wire.

If everybody in the US with a 95-99 3800 changed out their O2 sensor every 40-50K mi, or after their UIM and/or LIM gaskets crapped the bed, we'd use about 1MM less barrels of oil a day. (IMHO)

See what you get.
charliemax is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
3.1L P0300 DTC 'Random/Multiple cylinder misfire' Ben Cartwright General GM Chat 2 08-09-2013 10:27 PM
2000 s-10 random cylinder misfire s10owner Chevrolet 8 01-11-2013 08:14 AM
P0300 misfire help (fixed) midwboss Buick 13 10-20-2011 02:04 PM
Misfire Cylinder 6 (Fixed) azu 1992-1999 32 07-13-2007 12:52 AM
Random/multiple misfire, cylinder # 3 zeroburnz 1992-1999 33 04-06-2006 11:57 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 08:53 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.