1996 blazer...misfiring.. p0300 and p0140...rich smell and while driving at normal speed bucks and sputters but under accelleration doesn't miss at all...new wire/cap/button/plugs/cleaned egr..nothing changes...done a water mist test on wires and cap last night and could see spark jumping...i'm lost

 

Have you read these threads? I think the one you should be most concerned with is the first one. P0140 should not be causing a drivability issue.

P030x Explained (x=0,1,2,3,4,5,6)

Anybody know what code P0140 means

 

P0140 has no impact on engine performance.

Have a read through the P030x thread and the link to the rather lengthy P0300 thread at the bottom of the diagnostic page.