i had some snow in the air box which i belive caused my cat to plug up i cut the cat out and put glass pack in for the time being put new plugs and wires in cleaned both o2 senors and maf sensor and it still rolls a little black somke and im geting 8 mpg at 50 i was geting 18 before the issue happened im putting the cat in today. any thoughts on what the problem could be im thinkn replace both o2 sensors(this is going on on the passenger side). also its got true dual cat back stratights with 90 exit. checked plugs and they were black seems like the 02 sensors are telling it to give it a little more fuel that its able to burn off thus the black smoke. any thought or ideas would be great