my 4.0 hasnt been acting right. i know the renix engines do their own things, but mine has been idling a little high. and when i slow down i can feel the engine fighting the brakes. sometimes when in neutral or park it will idle at about 1500 then drop to 1200 and go right back up and do this over and over. And if it is idling high, i tap the throttle and it goes down to about 800. I have been checking for vacuum leaks but no luck yet