I need help forum! Misfiring BAD
03-15-2010, 10:44 AM
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I need help forum! Misfiring BAD I have a 1999 Camaro Z28 LS1. Up until recently the car started to misfire at lower rpm between ~1200-2800 rpm. When ever I would hit the car regardless of what gear I was in, it would stammer and studder and then all of a sudden it will get its power back. This problem happens at random times with no warning or consistency. It occasionally trips an O2 sensor code but only sometimes trips a misfire code.
It showed a random misfire code (or P300). I took it to my mechanic and 7 out of 8 cylinders were misfiring. He recommended we change the spark plugs and see what happens. We did that and the spark plugs showed signs of the engine running lean. But after we changed then, it took about 3 days before it started misfiring again. We hooked up his scan tool and saw that the whole left side, and only the left side of the engine was misfiring (cylinders 1,3,5,7). We checked the fuel pressure and it was at 59-60psi. We changed the fuel filter, and I replaced all the injectors with brand new Ford racing "Red tops" 36lb. We cleaned the Mass Air flow sensor with some brake klean and cleaned the K&N filter. The problem still exists. Any ideas at what could be causing this? Please help me out here!!!
It showed a random misfire code (or P300). I took it to my mechanic and 7 out of 8 cylinders were misfiring. He recommended we change the spark plugs and see what happens. We did that and the spark plugs showed signs of the engine running lean. But after we changed then, it took about 3 days before it started misfiring again. We hooked up his scan tool and saw that the whole left side, and only the left side of the engine was misfiring (cylinders 1,3,5,7). We checked the fuel pressure and it was at 59-60psi. We changed the fuel filter, and I replaced all the injectors with brand new Ford racing "Red tops" 36lb. We cleaned the Mass Air flow sensor with some brake klean and cleaned the K&N filter. The problem still exists. Any ideas at what could be causing this? Please help me out here!!!
03-15-2010, 11:20 AM
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FormerVendor
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Bent pushrods, coil, broken valve spring, wires, vacuum leak, bad mass air meter...could be any number of things. I really hope you have a correct tune for the bigger injectors. Never replace with performance parts when trying to find a problem you could just compound the problems.
Huh??? 
