1989 Honda Civic installed a water pump and car wont run ri

I installed a water pump and marked all the pulleys so I wouldn't mess up the timing.
So the problem is that I start up the car and it idles low but when I put in reverse it goes and then when I put it in drive it goes to 2500 rpm and stalls and has a tuff time going forward. So could you help I checked the IAC valve and nothing and checked all the hoses and double checked all the bolts and belts. I can't figure it out and don't know whats up. I took my car to two mechanic shops. Prior to the other problem I have had a problem with my gas it constantly goes up and down when idling. No vaccum leak and compression is good and I have spark. ?HELP?