# Multiple Missfire



## 05PTGOAT (Jun 8, 2009)

I recently did a Cam, Lt's, catless mids install. After we got it finished and installed i had some multiple missfire's. So i just went and replaced the plugs and wires. I did ac delco plugs and msd wires. That solved it for about a month and now its back doin it again and throwin codes. Any reasons why it keeps comin back. Or how to fix it. (i did have a tune on it after the mods) 
THANKS


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## Bluegoat05 (Mar 22, 2010)

that sounda like what happened to my silverado.. go and get some dyelectric grease, i dont know how to spell it, and put it on both end of your wires that will ensure a proper electrical connection. and then if you still have misfires try changing the coil of the misfiring cylinder with one that is not misfiring.. hope it helps


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## 05PTGOAT (Jun 8, 2009)

Ok thanks I'm open to try anything. Are Ac delco plugs the best plugs for the gto?


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## jpalamar (Jul 22, 2008)

I would have the tune checked out. Also depending on the size cam/mods you might want to look into bigger fuel injectors as well.


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## 05PTGOAT (Jun 8, 2009)

Well the cam is a torquer V2 232/234 595/598 with 112LSA. And ill get with the guy that tuned the car. Whats the price on new injectors?


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## 05PTGOAT (Jun 8, 2009)

Also it only happens at a idle. The check engine light 
starts blinking. And when I get movin it stops like it goes away. The code it throws it random/multiple missfire. Hope that helps u guys help me solve it


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## KyleGT05usmc (Feb 28, 2009)

Hmmmm. My LT1 camaro did something like that and turned out to be the ICM

not sure if the LS2 uses similar system. 
could also unplug each coil 1 by 1 to see which is causing the misfire(whatever doesnt change the beat of the engine is the culprit). that at least narrows down to what cyl(s) is misfiring. 
again not really familiar with the LSX inputs but a possible crank position sensor error? if you have oil or something leaking from cam install down towards the crank that could be a problem. 

could not be a ignition issue at all, as jpal said, might not have the right A/F mixture at idle...


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## 05PTGOAT (Jun 8, 2009)

Well I'm I'm gonna call the guy that tuned my car today I guess and see what he says about it. But I'll also change the plugs since there under warranty. Thanks for the help


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## 05PTGOAT (Jun 8, 2009)

Well I changed the plugs , changed the wires, changed the upstream o2 sensors and still got random/multiple miss fire. Any ideas on where to go from here?


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## 6QTS11OZ (Mar 27, 2005)

05PTGOAT said:


> Well I'm I'm gonna call the guy that tuned my car today I guess and see what he says about it. But I'll also change the plugs since there under warranty. Thanks for the help


The best thing to do is go see your tuner before you throw any dime into it. You've seem to have done all the simple things that one should do when a missfire occurs and you still have the problem. Plus since this happened after your mods were installed and the tune, I would point to a problem being in the tune. I think it lies in the timing (spark advance) since it seems to happen when it idles and then goes away when you take off. A simple bump in timing may solve your problem.


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## 05PTGOAT (Jun 8, 2009)

Well I called the guy that tuned my car and I mentioned could it be a timing issue and he ruled that out right away. All this missfire came on gradually. It just started gettin worse so idk what it could be. Could it be any sensors like cam pos sensor?


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## 6QTS11OZ (Mar 27, 2005)

05PTGOAT said:


> Well I called the guy that tuned my car and I mentioned could it be a timing issue and he ruled that out right away. All this missfire came on gradually. It just started gettin worse so idk what it could be. Could it be any sensors like cam pos sensor?


Instead of your tuner "ruling out" what _may_ be the problem, why in the hell don't he have you to bring the car back in and make a real attempt to help you out? Playing the guessing game is gonna cost you a lot of money. Good luck with that.


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## 05PTGOAT (Jun 8, 2009)

Yea ur right I'll call him first cause that will be alot cheaper. Thanks


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## grr's goat (Apr 25, 2010)

my car does the same thing. its all in the tune. it gets better when the weather gets warmer out. it should be a simple fix for the guy that did the tune.


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## GymChamp (Jan 10, 2010)

*Replacing ignition coils solved misfiring*

Could really feel it wasn't hitting on all cyls and missing on more than just one. The infernal "Check Engine" light was blinking & off & on & over & over. The missing was intermittant, coming and going, so I thought it was some bad gasohol. Nope: Diagnostics showed it was not firing on no. 7 or no. 8, that the coils were the problem (each cyl. has its own coil you know). Replaced both coils and WOW. I think one went bad for a short while & then when the second one died soon after it was very dramatic -- going down in flames, sputtering all the way down. Strange though, that 2 coils go out nearly the same time, on a cherry '06 with 25k miles that sits in the garage 25 days a month, & never goes to the track or strip. Repairs cost me $571. OUCH. That was gas money plus a few lunches too. I Hate when stuff breaks or falls apart for no good reason and costs a small fortune to repair... my money goes down a hole and it makes me wonder how well my pride & joy is made.


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## Rukee (Feb 8, 2007)

Why would it cost that much? Even at NAPA the coils are only $149.14 prt# ECH IC534. 2 coils would be $298.28. It takes almost nothing to swap them out.


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