Feeling a bump between 10-20 miles per hour

I have had trouble starting my '99 astro van, will start after about 5 min. of trying to start and then starts up for the rest of the day no problem. Also I feel a jerk or bump betweeen 10-20 miles per hour. Assumption is first asnd second gear missing for some reason. HELP I don't want to junk but maybe going down that road. By the way just fixed fuel pump and a major tune-up.