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

 

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...

 

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.

 

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