I'm having problems with my car missfiring. I have an LS/VTEC Turbo and it's got a t3/60-1 turbo and It's got a problem of Missfiring after vtec. It putts and lags too make power for a few seconds then goes again. 1st and 2nd gear its fine, but in 3rd gear when it hits vtec it just putts and sputters. Also on cylinder 4 the spark plug is caked with oil and its brownish in color. It also blows smoke when it spools at 4000 rpm and at idle. Can it be Return and feed line issues?

 

i think you have 2 issues there.

the puttering i think is ign related. also with the oil in the plug hole that isnt helping either. replace the vc gasket and the plug tube gaskets, make sure the ign system is up to the task, and go back and look at the oil return.

unless you mistook the blue smoke for black. if it were misfiring.