Since repalacing the flow control valves, it wasn't until 1200 miles until the check engine oil level warning came on. However, I noticed on Friday as I was driving in very hot weather, that sometimes when starting from a stop, there is a lack of throttle response, a lag or a hesitation if you will. There is no EML light to come on and I get no other warnings on the dash. Do you guys think that maybe there is another vacuum leak since the three which were fixed 1month ago or do you think maybe the DK motors are going bad or what?