I WAS DRIVING MY 91 ELDORADO TONIGHT AND WAS GETTING ONTO THE FREEWAY AND HAD TO STEP ON IT,AND IT ACTED NORMAL,THEN CUT OUT,AND HAD VERY LITTLE POWER,AND WAS GETTING POOR MILEAGE,AND I DONT KNOW WHATS WRONG WITH IT. IT SOUNDS LIKE AN OLD SUBARU,LIKE MAYBE IT IS NOT HITTING ON ALL 8? I HAVE NOTICED RECENTLY THAT WHEN I LET OFF THE GAS AND COAST THE ENGINE "BUCKS" A LITTLE. NONE OF THE ENGINE LIGHTS CAME ON,WHEN YOU START THE CAR BACK UP THE COMPUTER SAYS EVERYTHING IS OK. ANY HELP WOULD BE GREAT!

 

how long since it was tuned up?