Help with my 90 prelude

iv owned my prelude for about 7 months now. when i originally bought it there were some problems with it not starting occasionally. i would just wait 5 minutes and it would start when i tried it again. over the past months it became slowly worse starting less and taking longer to start again. a couple of weeks ago it finally stopped starting at all and i had to take it into the shop.
i was referred to a shop by a friends father who owns a salvage yard and takes all of his cars there. he never had any problems with them and they would give me a discount so i figured they were reputable. after they checked it out they determined it was the fuel pump that was causing it not to start. they put in a new fuel pump and everything seemed to be working fine. on my way home right before i reached my house i came to a stop at a stop sign and the car stalled. it would restart but every time i came to a gradual stop the tac would drop to low and it would stall.
at that point i took it back in and told them the problem. i noticed it was idling low and pointed that out to them. they fixed the idle and had me test drive it to make sure it was working. it worked for the first couple of stops and then started stalling again.
when i took it back to them they told me they would check it out some more. they said they wouldn't charge me for labor, only parts that were needed. after a couple of days they told me that the problem was the relay. they put a new relay in and a new fuel filter and told me it wasn't stalling anymore.
i took my car back home and didn't have any problems with it stalling at all. in fact if anything the car seemed to be running better than ever. the only thing i noted was that when i started it the tac would run a little high but it would drop down to normal once i started driving. it has worked ok for the past 2 days (although i didn't drive all that much) however, when i went to go up to the store about an hour ago it stalled again when i was turning into the parking lot. i had almost come to a stop while turning so i am guessing that tac dropped low again.
My question for you guys is: does anybody know what might be wrong with my car? i am afraid to take it back to the shop as i don't know if they did something to it out of ignorance and will just charge me for some random part fixing nothing. i don't have a whole lot of money at the moment and may have to barrow some as is. all help would be greatly appreciated by me as i don't know much about mechanics. thanks to everybody who has any suggestions.

is it a S or a Si?....if its a S the floats in the carb could be sticking.