98 s10 p0300 code

Goin crazy. This P code is killin me. I have installed new plugs, wires, cap and rotor, and all 3 O2 sensors. Reset code. Lasted about 3 weeks then came back. Truck idles as smooth as glass but can feel the stumbling when taking off and at highway speeds. I have read it seems like tons of things about this P code. Need some advice before I start dumping money where is doesnt need to go. Can anyone help me out??

You should check your fuel pressure. You could have a clogged fuel filter. If your idle is a little higher than normal, you could have a vacuum leak. You could have a vacuum leak even if it is not high.