Do you seem to be down a cylinder and running on 3? Fire up the engine and pop the hood,start taking the spark plug wires off the plugs 1 at a time..if you get a change..as in the engine starts missing put it back on and go to the next...if you find one that makes no different in how the engine is running when you pull the plug wire off then you know this is the cylinder of concern. THen as the guy above me said start checking for spark on that cylinder,might be a clogged fuel injector as well as he said..I have had this happen. I had a miss on Cylinder #2 after I did my LS swap into my EG. I had spark,good compression..I pulled the injector..it looked ok to me..but I put it over in cylinder 1 and put the injector from cylinder 1 over in 2..fired it back up..now the misfire was on cylinder 1 instead of 2. Bought a new injector and problem solved.
Months later my car died on the way home from work one day..wouldn't do anything..would not re-start or anything. Had to have it towed home. Paid the tow truck driver 85 bucks..he left..I tried one more time to start and shit..it fired right up..not what I wanted..I knew it was electrical. I drove it to my dads place 10 mins from my shop to get his spare car while I figured this out..on the way it lost power..tachometer went to 0..but the engine was still running..oil pressure was still at 75psi...just had no power..it died when I pushed the clutch in...I swapped to my spare dizzy and no more problems..