Ok from the top...
When I'm idling in park, pop the hood, and hold on to the engine I feel slight bursts of vibration. I can also slightly see the vibrations. It can be best explained as a sputter or short bursts of lost fuel. I'm not sure, I just threw "fuel" in there because thats the first thing that comes to mind. My ignition system is just fine, except my plugs may be a little darker than usual due to nitrous passes. But I changed the plugs about a month ago and havn't been that crazy with the laughing gas since.
I just put a new o2 sensor in (NAPA, ok so far) and dumped some more fuel injector cleaner in yesterday. So heres what I'm thinking:
1.) Clean fuel rail fittings, then clean injectors by hand.
2.) Fuel Filter? (currently Fram filter I put in this previous winter)
3.) Fuel Pump? (don't know much about my fuel pump at all)
4.) I'm going crazy.
Inside the car, sitting at the wheel, you honestly can't feel the vibrations unless you're being extremly anal and waiting for the slightest bump. I did push the thottle in slightly when at the engine compartment and after holding it at a particular rpm I could sometimes feel small twitches or sputters.
So what do you all think? Am I finally going crazy???? Or do I simply need to go through some overhaul?