# Help:LS1 misfire(FIXED) **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [February 5, 2009, 6:11pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557 "2009-02-05T18:11:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 6:11pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/1 "2009-02-05T18:11:29Z")
Car: 1998 Pontiac Firebird Formula 93k LS1 M6 Problem: SES intermittently flashing(HOWEVER DOES NOT THROW A CODE!) Tried solutions: 8 new plugs (NGK Tr5 V power plugs) New Autolite 7mm wires ACDelco coil pack Story: My SES light started flashing. I had it checked out and I have absolutely NO codes being thrown. I think the computer isn’t sophisticated enough to log the problem. I had a rough idle, my whole engine was shaking at idle badly. I changed the plugs and wires with what I listed above. All the original tr55(Yes double 5) plugs looked nothing out of the ordinary, with exception to the second towards the rear of the bay on the passenger side which reeked of gasoline. Drove the car after replacing the plugs and wires and still had the Service engine light flashing(and the new tr5 plug in the same spot smelled like gas). Therefore I replaced the coil pack. The car now idles much smoother, sounds better, and runs better. However the service engine soon light still flashes every now and then! No power loss at all. Seems to only trigger the SES light at light throttle.(Over 25mph) Any help? -Sobo ---
**Author:** ![psychopjv](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/psychopjv/32/7251_2.png) [@psychopjv](https://forums.speedlife.net/u/psychopjv)\ **Post date:** [February 5, 2009, 6:17pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/2 "2009-02-05T18:17:36Z")
if that light is on it’s logging a code or you have some sort of wiring issue. A scan tool hooked up to the car while running will log actual misfires and even tell you which cylinder is doing it, and graph it real time. Could possibly be a cam sensor on the way out even a crank sensor issue though these are not as common on stock. ---
**Author:** ![Firehawk853](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/firehawk853/32/7607_2.png) [@Firehawk853](https://forums.speedlife.net/u/Firehawk853)\ **Post date:** [February 5, 2009, 6:18pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/3 "2009-02-05T18:18:21Z")
Is there a noticable power reduction while its flashing? ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 6:20pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/4 "2009-02-05T18:20:50Z")
Not at all. Seems to only trigger the SES light at light throttle. I had Firehawk853^ check the car out and there was nothing… Maybe wanna go for a ride with me with your lappy hooked up and see if it gives you anything man? ---
**Author:** ![Wahoo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wahoo/32/8265_2.png) [@Wahoo](https://forums.speedlife.net/u/Wahoo)\ **Post date:** [February 5, 2009, 6:24pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/5 "2009-02-05T18:24:03Z")
O2 sensor’s? just throwing that out there i know the cats clog easily and were a problem which is why they were warrantied for 12 years 120,000miles so maybe something like that since you say power doesnt seem to have been lost. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 6:26pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/6 "2009-02-05T18:26:21Z")
I have no cats. I’m running pace setter long tubes, to an off road y pipe, to borla-mouth. I have upgraded Bosch o2’s for the front ones, and my rear o2’s are deleted. I had Firehawk tune out everything and check out my car and there is absolutely no recorded logs of the misfire problem. ---
**Author:** ![Wahoo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wahoo/32/8265_2.png) [@Wahoo](https://forums.speedlife.net/u/Wahoo)\ **Post date:** [February 5, 2009, 6:31pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/7 "2009-02-05T18:31:07Z")
> [@sobo](#): > > I have no cats. > > I’m running pace setter long tubes, to an off road y pipe, to borla-mouth. > > I have upgraded Bosch o2’s for the front ones, and my rear o2’s are deleted. I had Firehawk tune out everything and check out my car and there is absolutely no recorded logs of the misfire problem. Sorry i should of checked your profile! Well wish i knew more so i could help. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 6:33pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/8 "2009-02-05T18:33:03Z")
All my plugs with exception to one were perfect. I replaced plugs and wires on all, and on the one plug that smelled like gasoline, i replaced the coil pack too! The engine runs fine, and doesn’t shake at any low rpm which means all the cylinders are firing at that point. ---
**Author:** ![Gus](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/gus/32/5112_2.png) [@Gus](https://forums.speedlife.net/u/Gus)\ **Post date:** [February 5, 2009, 6:48pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/9 "2009-02-05T18:48:40Z")
Check your grounds? Maybe you have a bad resistance in that injector dumping too much gas. And I think I speak for everybody from the LT1 world when I say… HAHA!! GL! You’ll figure it out. ---
**Author:** ![Studderin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/studderin/32/7197_2.png) [@Studderin](https://forums.speedlife.net/u/Studderin)\ **Post date:** [February 5, 2009, 6:57pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/10 "2009-02-05T18:57:08Z")
The signs point to something up with cly6 witch you noted of the plug. You said you changed the plugs, wires, and that coil and it still fouled the plug. Its a 98 witch have some more downfalls, it should have the perimeter bolt heads, so you have no coil brackets making this a little more difficult. But I suggest you swap the coil pack harness, from passenger/driver side. And see if the issue moves with the coil pack harness. If its still #6 and its a M6 car I’d check for a bent push rod on #6. But check them all. Tons of m6 cars have bent pushrod and there no sings at all. And check the grounds, 3 on the rear of the heads, the 1 to the block form the harness near the starter wiring. Other form the block behind the alt. the the driver side frame rail under the underhood fuses. I’m not 100% sure on the 98s, one of them on a back of the heads is for coils. Do you get spikes of 4\* KR when you feel missfire on the light loads. Its a 98 they have the problem, of 4\* false knock. It’s the knock sensors and the harness. Its a good upgrade to change them for 99+ ones. More so a camed car, but if you have a bend pushrod(s) it was have the same susceptible affect. I think the SES light flashes on a 98 car from that too, but mostly is is from a P0300 random/multi missfires. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 7:02pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/11 "2009-02-05T19:02:54Z")
I never feel the misfire. I just see the light blinking. The plug never fouled either, and I haven’t pulled the plug I just put the coil pack on today. I’m gonna run it another day and see if it maybe finally threw a code. On the old plugs nothing led me to think that I’m running rich or lean all plugs seem in normal condition. I’ll check the grounds but I don’t think they are the culprit. Maybe the harness, but I sincerely doubt the grounds are of any issue. I have no idea what you mean by 4\* KR. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 7:09pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/12 "2009-02-05T19:09:21Z")
I feel like just dumping it off at the dealership and letting them figure it out… Because now i’m lost. ---
**Author:** ![Studderin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/studderin/32/7197_2.png) [@Studderin](https://forums.speedlife.net/u/Studderin)\ **Post date:** [February 5, 2009, 7:16pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/13 "2009-02-05T19:16:14Z")
I’m lost to, you said the plug 2nd form the rear passanger side was soaked in gas, you changed it. same plug reeked of gas. But you just said you think “all plugs seem in normal condition” ? No offense you need to have somone that know more look at it, and see what it is and isn’t doing. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 5, 2009, 7:20pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/14 "2009-02-05T19:20:43Z")
No, it was soaked in gas before I took anything off. Then I replaced plugs and wires. Drove it for 20 miles or so, after noticing the blinking SES still came on, I pulled that plug, and noticed it smelled like gas. I cleaned it, then put it back in. I replaced the coil pack today, went for a drive and the SES is still blinking. I have not checked that plug since. By saying “all plugs seem in normal condition” I mean they are not excessively dirty, or burnt so its not running lean or rich. I suppose that cylinder is not igniting at all, or at least it wasn’t ---
**Author:** ![Firehawk853](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/firehawk853/32/7607_2.png) [@Firehawk853](https://forums.speedlife.net/u/Firehawk853)\ **Post date:** [February 5, 2009, 8:45pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/15 "2009-02-05T20:45:14Z")
when I get back in town this weekend we can take it out and get some scan logs while your driving. Assuming the weather is nice enough… ---
**Author:** ![psychopjv](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/psychopjv/32/7251_2.png) [@psychopjv](https://forums.speedlife.net/u/psychopjv)\ **Post date:** [February 5, 2009, 8:49pm UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/16 "2009-02-05T20:49:49Z")
He’s saying it ran like ass so plugs/wires were done. still ran like ass. plugs checked. #6 fouled out. coil pack was changed due to non firing. Car seems better. Could def be a knock sensor. Was the motor ever cleaned off with water? people do it and don’t dry it properly and it can pool in the knock sensor, rusting it out and killing the sensor. This usually is accompanied by running like a bag of ass though. Thats what Studderin mean by 4\* KR. 4 degrees of knock retard. AKA it’s pulling timing because it is detecting knock/ knock sensor circuit has a failure. Like i said in the first reply, it needs to be hooked up to a real scanner (tech2,modis,brick,genesis, even HP tuners) so these things can be monitored and evaluated while idling/ driving under load. ---
**Author:** ![LZ1](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@LZ1](https://forums.speedlife.net/u/LZ1)\ **Post date:** [February 6, 2009, 3:44am UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/17 "2009-02-06T03:44:02Z")
Those pacesetter Y pipes suck…you probably have a leak and its fucking up with the O2… I had the exact same issue on a 98…with pacesetters and a shitty Y pipe…ended up welding the y pipe… ---
**Author:** ![Studderin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/studderin/32/7197_2.png) [@Studderin](https://forums.speedlife.net/u/Studderin)\ **Post date:** [February 6, 2009, 6:06am UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/18 "2009-02-06T06:06:52Z")
ya, what pat said. but I didn’t want to get into it that far yet, on the 97-98 LS1 knock sensor deal. lol what are you using to scan it? Its a 11 year old car with 93K miles and its getting driven in the winter, it could very well be a damaged ground wire. Don’t over look that. start at the basics and go from there. ---
**Author:** ![sobo](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sobo/32/5267_2.png) [@sobo](https://forums.speedlife.net/u/sobo)\ **Post date:** [February 6, 2009, 11:09am UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/19 "2009-02-06T11:09:11Z")
11 year old car that was never driven in the winter untill the 3 times i did this year. Whatever Firehawk853 uses to tune Ls1’s, is what was used to check over my car. It was a florida car… but i will check it out. ---
**Author:** ![Studderin](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/studderin/32/7197_2.png) [@Studderin](https://forums.speedlife.net/u/Studderin)\ **Post date:** [February 6, 2009, 11:22am UTC](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557/20 "2009-02-06T11:22:40Z")
Ya its had over the web, let use know after you check the things listed. If I saw the car I could find it out quickly. did the missfire codes get turned off? [Next page](https://forums.speedlife.net/t/help-ls1-misfire-fixed/62557.md?page=2)