Question

2001 suburban which hesitates slightly at intial accerleration from an idle of 500rmp. If you let up on the gas the rpm will go down to 250 rpm before recovering . Sometimes on a tight turn from a stop the engine will die. Also, sometimes when accelerating and shifting from 1st to 2nd the car will get into a sort of a loping mode were the engine appears to momentarily die and the start running again no matter how much gas you are giving it. These are the symptoms my daughter is giving me. I have not been able to make this happen, but I have verified the low rpm and hesitate. Any ideas on what is causing this (fuel or electrical). What do I try? Also While trying to experience these symptoms I noticed that the ABS Brake pump is making a high pitched noise. Will this pump continue to work for a while or is it domed pretty soon.