for the past few days, when i go to start the car it makes a real quick squeak kinda like a loose belt for a split second when it starts. The car runs and starts just fine besides that squeak...Anyone got any ideas? Also, do these engines run rougher at higher rpms the more miles you put on them? mines got 63k and you can really hear the valvetrain, especially at higher rpms, it doesnt sound anywhere as smooth as it used to.