Misfire under boost - Page 4 - 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.

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Old 12-21-2005, 01:00 PM   #31
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Ok, you've heard me say it before, but it happens again......never assume new plugs and wires can't be a problem. If you have a spare plug wire, patch it in at the #3 position. If not, check the resistance of the 1, 3, 5. Should be an even progression across the front bank. Then CAREFULLY inspect that #3 wire for a tiny black spot where it may be arcing to ground. Make sure the wire isn't touching anything. It can even arc from one wire to another at times. Seperated it from the rest temporarily if it'* in the factory retainer.

In addtion, I assume you've already checked coils? Try swapping coils. Move them around.
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Old 12-21-2005, 01:19 PM   #32
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ok well ive got about 15 wires i can try out from my stock wires, the replacements and the ones i just bought, but i really doubt i got 2 defective wires in a row on the same cylinder, if it was a coil wouldnt ilose 2 cylinders tho? right now im thinking vaccum leak or injector, do any injector cleane rlikelucas actually work or woudl i be looking at the $75 for a new injector?
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Old 12-21-2005, 01:25 PM   #33
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Swap the #1 and 3 injectors. If the problem moves, get a used one from a wrecker.

Coils CAN get weak. You may only be seeing the early stages.

A vacuum leak would likely be the LIM on your car.
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Old 12-21-2005, 06:21 PM   #34
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To me checking the coils is a no-brainer. It only takes a few minutes & could save you a lot of aggravation. You can check the secondary side or the coils while they are on the car. Just pull the spark plug wires off each coil & check the resistance across the posts. All three redings should be very close.
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Old 12-22-2005, 03:25 PM   #35
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ok i got the coil resistances, they seemed pretty clos ebut the coil attached to cyl 3 was lower than the other, the first 2 coils were 5.3X Kohms, and the one for cyl 3 and 6 was 5.25 Kohms, is that normal or what? also bout checking the injectors, just to be safe do you just unbolt the fuel rail and it all pops off? and is there anythign i should watch out for while doing it?
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Old 12-22-2005, 03:28 PM   #36
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Your coils sound fine, but check them again soon when the car is hot. Open the hood and work rapidly to get hot resistance readings.

On the fuel rail/injectors, you are correct. Unbolt the rail and gently work it off with the injectors still installed. Then swap the #1 and #3 or the #3 and #5. Check for corrosion on the connectors while you're at it.

We'll nail this one. It'* just the basics that are a possible issue here.
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Old 12-22-2005, 10:39 PM   #37
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OK new to this whole supercharged 3.8l thing but I have a similar problem. 97 ssei that auto zone says the number 2 cylinder is missfireing. replaced plugs and wires, and even pulled the wire off and started the car. It is number two that is misfireing but when I pulled the plug and bumped the engine over the plug fired just fine!! I was wondering if a bad O2 sensor could do this, cuz I as well thought it may be a vacum problem.

Let me explain how the check engine light originally came on, I was driving agressivly!! disconected the neg of the battery and the light flashes and then stays on! (sorry didn't see that disclaimer)

So please help, oh and by the way it'* the girlfriends dads car and hes a rather large man so I am trying to save myself a well deserved butt kickin'. Thanks
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Old 12-22-2005, 11:10 PM   #38
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OK another thing I just found was it may need a trans valve body replaced. Any one know where to get that cuz auto zone and advanced doesn't seem to carry them. Also would the trans send a fault code to the engine to under power it to try and save the trans? just a thought.
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Old 12-22-2005, 11:28 PM   #39
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i am aware that street racing stories arent allowed but please dont lock this thread mods, maybe just cut that part out of the post?
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Old 12-22-2005, 11:41 PM   #40
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Quote:
Originally Posted by fuzzy
OK another thing I just found was it may need a trans valve body replaced. Any one know where to get that cuz auto zone and advanced doesn't seem to carry them. Also would the trans send a fault code to the engine to under power it to try and save the trans? just a thought.
if you need the valve body replaced...and im not sure how u know that or how u found out...you need a trans rebuild...its not somethig you can do yourself
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