Is the engine still miss firing?

yes it still running but with a bad miss to bad to drive

I have a 1996 olds achieva will start but with a bad miss . coming home from work it ran like a new car then bam a miss low power so i scaned it and got code po300 and code po335 so i changed the crank sensor still no change o yes its a 2.4 L
and it acts like it out of time when you start it the motor turns fast like normal but ever so often it turns over slow like when one is out of time . think it could have jumped time? and on the missfire part it misses so hard you would think its going too jump out on the ground.checked the oil looks good and clean dont use any oil between oil changes has no smoke from the tail pipe. new tuneup 6 months ago new gas filter all i can think of anything you need to know just ask thanks for everyones help..