By that do you mean they don't stop, or that they stop for too long to let you through, thinking that you're not going stop at all? (Assuming it's a 4-way stop)

By that do you mean they don't stop, or that they stop for too long to let you through, thinking that you're not going stop at all? (Assuming it's a 4-way stop). If latter, then I could be that motorist as well -- I will naturally assume that cyclists will NOT stop at stop signs (since I have never seen them do so), so I would let them through preventively.