Happy_Doodle

I'm a obviously a newbie. I have an 87' t II and am having bad rough idle problems. It has a 3" turbo back exhaust, cold air intake (homemade). It idles at about 375 to 850, when warm. It wont idle if you just lift off the throttle you have to lower the idle to about 900 before it will stay idling by itself. Even then it lopes very hard. Other than that there is no running problems. I've tried adjusting the BAC valve it worked at first then just quit and I was stuck with a loping idle again. The loping doesn't bother me, the fact that it wont idle by itself does though. Any thoughts or theories on this situationwould be greatly appreciated. Another problem now I drained my coolant today and discovered it had oil in it! Not entirely sure (have no freakin clue) as to what kind of potential problem this leads to. Car runs fine. Any info. on this will also be greatly appreciated.