got a 99 grand am se 2.4l. it runs fine when it is warming up and all. when i gets to ~200 its ok for 5-10 min. then after that when i slow down (city driving) it will die. it wont even idle. i have to drive it like a manual and pop it into neutral to keep it reved enough to not die. it also seems like the gas pedal gets stiffer, almost like the something in the linkage is sticking. what should i do?