misfiring... again...
misfiring... again... 
well... car decides it wants to misfire again...(LAST NITE) Not the plugs, not the wires (I tested the resistance), changed the coil packs/harnesses, Is there a way to "test" the coil packs/harnesses... or what are the odds its the harness from the computer!? any suggestions !? Think this means Im not going to 41 w/ you guys tonite. 
Im about ready to crack open a beer and say **** it. 
Im resurrecting this thread!!! I thought I had it narrowed down to Valve springs,(5K miles) lol but it is an ms3 cam, that is driven pretty hard. but a friend suggested it may be a bad knock sensor? (I dont know how these work so I wouldnt even know how to pinpoint it even if that was what it was). Does anybody have any Idea what it could be? It drives fine until I try to get on it. It breaks up at wot and then runs/idles like ****. Hesitates when I give it throttle. When I find the gremlins living in my car, Im gonna f*ck them up!
If you have access to a computer try doing a log while you get on it it will narrow it down for you. Check your harness for any place it could be rubbing. The p0358 sounds like you have a short.
I dont have access to a computer. And I have already replaced the harness. Where else could I possibly look for a short? Where in lockport are you located? Im actually working up there Right on rte 7 and almost 355.
Im on the edge of lockport by 159th and 135th check your grounds too. Ls1's do funky **** when you have a bad ground/ missing ground. Check the back of the driver head that one causes the most misfires ive seen.
that connector did get jacked up last time I took my heads off, and I put a new one on. I wonder if maybe it came loose? Thanks for the input, I'll check it out tomorrow. If anyone has any other Ideas I'd appreciate the input!
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I checked the ground, it seems pretty solid. I dont have any idea what it could be. Does this sound like something a knock sensor could cause? Or would it more likely be the valve springs? Anybody have any other suggestions?
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Does it do it all the time or just randomly? My car used to misfire at random times after my LT's were installed and it felt like it was running on 4 cylinders. I put in new Bosch (Not sure of the number but they were high dollar) O2 sensors and it never did it again.
nah, it runs great until I hit it and pull it above 5K rpms. Then it continues to run like ****, hesitates from a stop, idles real high. Engine light comes on. Then I turn it off, and it cools down (say overnite) the next day, the engine light is off, and it does the same thing... Runs great until I rip on it... etc. etc. etc.. lol. Its been driving me crazy!
I can attest to this car breaking up very badly at 100% throttle over like 4.5K rpms. These cars don't have any kind of fuel cut do they? You never did get tuned after you ls6 intake install maybe your maxing out the injectors and the computer is shutting the cars spark off?
sounds a little too easy but clean your MAF. i have seen lots of LS1 cars run shitty due to a dirty MAF. especially cars with k&n filters because the oil from the filter will get on the sensor.
Have you checked the connection from the alternator to the PCM? It could be there. If the PCM isn't getting it's 10v from the alternator it can cause funny problems. Could be a bad alternator or a bad wire. Have the alternator checked and follow the wires back from the alternator plug to the pcm and make sure there isn't anything wrong.
I believe that p0358 indicates cylinder 8. I dont have a k&n filter so the maf Is unlikely, and my altenator connection is solid. Thanks for the input guys, please keep them comming! Does anybody in the area have a scanner so I could check to see if it is a knock sensor or not?
My car would misfire the opposite way, and when it was wet out. Down low the sputters would practically shake the car, so I would romp on it and it would ease up. Bad coil packs. As for checking them, take the wire off the sparkplug and stick your finger in haha. Im jp. But if you need an extra hand in the area...hit me up. I might be able to get a scanner for a few days.
Just changed the plug, wire, harness, and coilpack ....not the problem. Pulled the valve cover, pushrods are fine, as are the springs. Switched the fuel injectors, and it started misfiring worse.... Then I had the codes check at autozone, same code p0358. Drove it home... and it runs fine now!? we're thinking its the pcm. Anybody have one lying around!?
we're thinking its the pcm. Anybody have one lying around!?