Coyle was given funds in the summer to recruit the likes of Keith Andrews, Andy Lonergan and Matt Mills and Gartside now wants to see some returns on the pitch.
"I can understand the reaction from the fans, and I was as disappointed and frustrated," he told the Bolton News.
"We had fantastic support at Hull and it was not good enough. There is absolutely no doubt, we have to improve, and I will be looking for a reaction.
"It is a good squad and we have made some quality additions over the summer, so we have to do better."