it all started when i got on the interstate and couldn't go over 3500rpm. pulled over to check oil and oil pressure light came on. checked my oil and it was about 1 quart low. put oil in and light went out. i then got back onto the interstate. drove about 2 miles and the engine went to clattering but not loud. i let off of the gas. the noise stopped. so i gave it a little gass and tried to make it to the next exit and the car shut down soon after. still have lights and it still turns over. but won't start. could it be timing or oil pump?