I have a 1996 GMC Yukon with a 5.7 Ltr engine (vortex). I am having an intermittent miss between 20 and 60 MPH. It is more pronounced in 3rd gear, and less so in O/D. The code has come up as a misfire on cylinder 3. I have replaced: Spark pulgs, spark plug wires, dist cap, and rotor, and have put in all new injectors. Still the code comes up Cyl 3 Misfire. Can anyone suggest what the problem may be? Thanksfor the help!

 

Probably a leaking intake manifold gasket.