Rough idol and engine missing

On my 95 Blazer the engine is idoling rough its also missing its a 4.3 motor and it has been tuned up, also the fuel regulator has been replaced. Could it be an o2 scenser?
joe

is there white smoke when you start it then goes away? mine does the exact thing. i replace my cpi, oil lines,wires,cap,rotor,plugsdid a motor and rad flush and still the same... i think its a lower intake gasket

Try cleaning the EGR valve.Take it off and spray inside real good with PB blaster or brake cleaner

well the egr is new, I ran into a friend and he scaned it and the air temp circut came up soo i'm gonna replace the scencer an see wut that does

Well I found out the reason for the air sencer prob the wire was off the only other code coming up is for a misfire on cyl 3. anyone no wut would cause that? I also found some corosion on the coil wire by the coil side could that be part of the problem?
Joe

make sure that wire wasnt melted by the header it happens all the time..