1999 Chevy Tahoe Engine Misfire

I have a 1999 Chevy Tahoe, 5.7 Liter 350 V8. I have a misfire issue on Cylinder #4 as diagnosed by a certified mechanic. I have replaced the spark plugs, wires, coil, and all four Oxygen sensors with OEM parts chasing a resolution to the problem. The vehicle will idle fine when not in gear and seems to run fine up to between 1600 and 1700 rpm range. This is when the misfire becomes apparent. At first I thought it may have been a transmission slip so I had checked and was told the transmission was fine. I also had the trans filter and fluids changed and installed new U joints just in case. I feel like I am just throwing money at the problem grasping for resolution and would sure appreciate some professional advice on where to look next. Could a dirty fuel filter cause only one cylinder to misfire? It has a throttle body on it and is not fuel injected best I can tell. I am a shade tree do it your-selfer, but admittedly do not know all there is to know when it comes to diagnosing the problem.