lq9 408 low rpm misfire help
08-09-2013, 11:22 AM
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lq9 408 low rpm misfire help well I just cant seem to figure this out. Lets start with what my setup consist of. Its an lq9 6.0l bored and stroked to a 408 ls3 heads vic jr single plane with an elderbrock elbow#3847,cam is a tick performance custom grind 248 257 duration
when at crusing speed and low rpm acceleration I can feel a miss fire or hell maybe sometimes multiple miss fires. but if Im at a dead stop and just punch it, it will not miss a beat at all and just put you in the seat. I have did logs and watched misfires and its all over the place until you punch it and the miss fires go away. Ive tried to move coil packs around but the miss fire counts seems to stay the same no matter were I put them. I just put a set of msd wires on it and it seemed to help some but the miss is still there at low rpm. It has pulled some codes I keep getting p0121 and p0300 just trying to see if someone else has had this trouble
when at crusing speed and low rpm acceleration I can feel a miss fire or hell maybe sometimes multiple miss fires. but if Im at a dead stop and just punch it, it will not miss a beat at all and just put you in the seat. I have did logs and watched misfires and its all over the place until you punch it and the miss fires go away. Ive tried to move coil packs around but the miss fire counts seems to stay the same no matter were I put them. I just put a set of msd wires on it and it seemed to help some but the miss is still there at low rpm. It has pulled some codes I keep getting p0121 and p0300 just trying to see if someone else has had this trouble
08-09-2013, 11:34 AM
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I've tried to unhook the maf sensor and that seemed to have no effect on it. I have pulled all the plugs out and cant seem to see a difference in the plugs. Also I have put the car in open loop so I can rule out the o2 sensors messing with it
