i have a 96 3.8 lt mustang,i jus bought is and it was shaking and using a lot of fuel,real slow on take off then it would gain speed,i then come to a hill and car slows down to a crawl,ive changed coil pack,plugs,wires,thottle body w/sencers,i need help,car does not knock and runs,i also had muffler shop check cats,and did compresson test,,,160 on all cyl,help,help