Ok i have a 1997 4.0 auto 4x4 cherokee , stock, i changed the oil in it being its new to my fleet and upgraded to the bigger filter put in 6.5 quarts of oil the same way ive done in all my 4.0 i6 and started it up . It ran but not right the idel would go up and down 750 to 1000 . then on the road about half the power of normal came home checked oil level . Was about a quart to much. let some oil out about a quart. took for a drive same problem. checked plugs cleaned em up took drive a little better but problem still there. took cap off shot some wd40 in took drive a little better but problem still there. i also checked for vacume leaks no luck .3 days ago i washed the engin bay with simple green and a hose I covered the computer and the cap with plastic, I drove it for those 3 days with no problems I also cleaned the thortel body at that time as well. Im lost . any ideas? Ps i used 10/30 oil and fram filter.