ve in98 5.7 cylinder 3 misfire and oil soaked
July 5th, 2007, 2:48 PM
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ve in98 5.7 cylinder 3 misfire and oil soaked
My truck has about 120 thousand miles on it and recently i have replaced the: cap, rotor, plug wires, updated fuel injectors with a new regulator ,pcv valve andintake gasket about 40k ago. It uses about 2 quarts of oil every 1000 miles. About every 150 miles i take the number 3 spark plug out and clean it due to misfires and it is caked with carbon and soaked with oil. I have tested the compression on that cylinder and it is up to specs and it has the same compresson as the other cylinders. Im wondering why this is happening. Could of i installed the intake gasket wrong, but if i did, it has been working correctly for at least 37k miles. The last time i had the upper plenum off to replace the injectors (about 8k ago) the cyl nuber 3 intake runner was very wet with oil and it looked to be coming out of the pcv valve inlet witch you can expect a small amount but this is excessive. I have asked sevral people and nobody has any idea. I would like to know somewhat what im looking for before i tare in to it again becuase it is my everyday driver. Any input would be greatly appreciated. Thanks
July 6th, 2007, 7:05 AM
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RE: ve in98 5.7 cylinder 3 misfire and oil soaked
The fact that your compression is still the same is probably what's throwing everyone off.
The only thing I could think of, which wouldn't effect your compression, would be the valve gasket for your intake side, on that cylinder only. Your rings should be fine since the compression is good.
It's probably been working fine for 37k miles because the part was new. The seal could have simply cracked, been defective, or something else. The odl GM S10-Blazers were notorious for prematurely blowing gaskets, valves, etc. around 40k-60k miles on the 97-2k models. So maybe it's just a defective valve gasket.
For fixes, try an addtitve which stops oil leak by lubricating the gaskets. Also, what type of oil are you running? The thinner the oil, the more chance it will leak. Worst case scenario, change the intake valves on that cylinder with new gaskets. [
]
The only thing I could think of, which wouldn't effect your compression, would be the valve gasket for your intake side, on that cylinder only. Your rings should be fine since the compression is good.
It's probably been working fine for 37k miles because the part was new. The seal could have simply cracked, been defective, or something else. The odl GM S10-Blazers were notorious for prematurely blowing gaskets, valves, etc. around 40k-60k miles on the 97-2k models. So maybe it's just a defective valve gasket.
For fixes, try an addtitve which stops oil leak by lubricating the gaskets. Also, what type of oil are you running? The thinner the oil, the more chance it will leak. Worst case scenario, change the intake valves on that cylinder with new gaskets. [
]
July 8th, 2007, 6:26 PM
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RE: ve in98 5.7 cylinder 3 misfire and oil soaked
Yeah when the intake was previously done i used felpro gaskets becuase i have had such good luck with them. I have been runing mobil 1 synthetic and yeah that oil is known for finding any leaks or bad seals. Well i will replace my intake gasket and hope all is well. Thanks for your help
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