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Cylinder 3 misfire.. on a Vortec 350.

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Old 03-02-2006, 09:28 PM
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Question Cylinder 3 misfire.. on a Vortec 350.

hey.. i have a 1990 Chevy Silverado K 1500. It has a GM Performance Parts 350 HO crate engine(Vortec Heads) in it.. I blew my transmission (700-R-4).. Didnt want to buy another one because the dealer wouldnt warranty it..

I upgraded to parts from my dads wrecked 1996 Chevy Tahoe. I took the intake manifold and and all the wiring off of the tahoe to make it a true Vortec 350. Also, swapped the dash and the transmission to the 4L-60E..
I have been having a few problems after the swap.. I had to replace all 4 oxygen sensors.. now it has all Bosch oxygen sensors.. and has AC Delco Platinum Plugs. It seems to start funny and idle drops sometimes.. i replaced the IAC Motor, the throttle positioning sensor, and the EGR but there still is problems. thats not the big problem now though..

A few weeks ago i was driving home from school and my Driver side before the cat O2 sensor fell out.. I had to replace the O2 sensor. I have a code reader and now i keep on getting a cylinder 3 misfire. it is also running rich on the driver side, because my tailgate is covered in soot. I dont know what is causing the light to come on.. i erase the code with the code reader, but the light comes right back on.. also, the service engine soon light flickers when i drive, instead of being on constantly.. I dont know what could be causing this.. I would like to hear some advice on what i should try to replace or what is happening. Hope to hear from someone..

Thanks
BRIAN
Old 03-02-2006, 10:03 PM
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If its running real rich, like soot on the talegate. I'd say the plug is fouled.. Really badly. Pull the plug and see if its black and sooty...
Old 03-02-2006, 11:09 PM
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yeah, because of the misfire you are getting alot of unburned fuel in the exhaust , whichj is than picked up by the 02 sensor, wheich would be why you thinks it running rich, Do a wet test , (lighty spray the ignition wires with a spray bottle while the truck is running, run the back of your hand across the wire, if you feel a light tingle or shock that your wire is arcing) trust me, it wont hurt you one bit, I am a mechanic for a living, people think that you will get shocked with an ungodly amount of electricity, YOU WONT. Also pull the plug and check it to see if it fouled.
Old 03-03-2006, 05:42 PM
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Thanks for the help guys.. I checked the spark plugs today.. they are not fouled.. my friend has a scanner. The timing was off a little bit,but now it is adjusted.. it was also saying something about a cylinder 3 and 6 misfire.. i replaced the cap and rotor and that didnt make much of a difference. Im thinking the injectors might be bad.. im not sure. i really want this problem to be fixed.. any other adive you guys could give me..
thanks
BRIAN
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