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.

Back again for help.....rough idle.

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Old 07-15-2006, 04:20 PM
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Did you try moving the plug to another cylinder? You could also swap the injector on #3 with another.

This article covers misfires.
http://www.autotap.com/Articles/Diag..._Misfires.html
Old 07-17-2006, 10:22 AM
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Good article on misfires, Ted. Still haven't had time to mess with it....working quite a bit until school starts back up. Gonna check the fuel pressure regulator and maybe try swapping that injector, although I will check it for leaks first as it is a fairly new injector.
The article mentioned that a major problem such as a vacuum leak would affect more than just one cylinder so after having done plugs, wires, swapping ICM and adding new coils the only other thing i could think if is injectors or something else fuel related. Ill double check the #3 plug to be sure its not fouled or anything like that.
Old 07-18-2006, 12:22 PM
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^ Bump
Old 07-18-2006, 12:36 PM
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Yes, do check the FPR, especially if you smelled fuel near it. Pull the evap vacuum hose from it and if there'* fuel in it, the FPR is going bad.

If that'* OK, I do suggest that you do a little coil swap experiment, even though you've already put new ones in. Swap one coil for another and see if there'* a difference in the error code as to which cylinder is mis-firing. Even a new coil will occasionally be bad.

On the other hand, don't ignore your vacuum lines. It never hurts to do a complete evaluation of your vac lines, including those under your airbox at the vacuum (charcoal) cannister. A smaller vacuum leak can sometimes confuse the PCM and the code you get may not be 100% correct. Plus, this is a cheap and fairly simple fix and it never hurts to have new lines.
Old 07-18-2006, 06:09 PM
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Originally Posted by zeroburnz
^ Bump
Did you get a chance to try anything yet? If you don't think it'* fuel or ignition related you could do a compression test.
Old 07-18-2006, 10:03 PM
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Had some free time today. Checked the FPR, no gas in the vaccum line it connects to. Pulled the plug for cylinder #3 and it looks fine, a few black marks but while running unplugged it from coil pack and its firing. Checked vaccum lines, found a few cracked connectors see pics below.

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I know its a little hard to tell from the pics but they are pretty much shot, especially the 3 way connector.

Also found the gasket on the front valve cover sticking out a little, dont't know if this has anything to do with the problems im having but just wanted to double check.

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Here'* another pic just for kicks:

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Wondering where i can pick up new connectors to replace those cracked ones. Any more ideas on where my problem might be?
Old 07-19-2006, 03:45 PM
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Hope the pics help as least a little. Will try switching a couple coils around as recommended. Otherwise the plugs, wires, and coils have been eliminated. Still thinking it is fuel related, but would a cracked vaccum hose connector cause a miss on only one cylinder?
Old 07-19-2006, 03:57 PM
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zero, while I can't answer you directly on the #3 miss, I can say that those connectors should be replaced asap. It would surprise you how much of a difference it can make. For the straight connectors, you can get a 1 foot length of each of 7/32" and 9/32" vacuum hoses and cut to length to replace all the straight ones.

Like I said, replace all the straight connectors while you are at it, including those under you airbox at the vacuum cannister. For the "T" connector, call or go to your local Pontiac or GM dealer. I paid about $3.20 for mine. I think somebody said they got one at their local AutoZone or Advance, but the ones near me didn't have them.

Replacing the cracked vacuum connectors on mine completely solved my mis-fire problems.
Old 07-19-2006, 10:12 PM
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alright, will get the T connector from the dealer. Question on the bulk hose though. Did a little searching and found this place:
http://www.stylinmotors.com/

Will silicone hose work ? If so what size in MM? thanks.
Old 07-20-2006, 10:09 AM
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Default Silicone vacuum hose?

Heard alot about how the OEM connections can become brittle and crack, also collapse, restricting airflow. I was thinking 4mm and 6mm (8MM is a little over 9/32"), since the silicone hose can be carefully stretched a little. Most places seem to want you to buy like 10 ft of the stuff. Found this kit at AZ:

http://www.autozone.com/servlet/UiBr...f+6mm+2+ft.+Of


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