It's not a mustang, but its a 1997 lincoln towncar signature. it has a v8 240hp engine. my problem is that when we rapidly accelerate or when we are in high rpm, the engine sounds like it is rattling and knocking around. it keeps getting louder and worse. my dad thinks it is the octane in the fuel level, but the guy who towed it when it broke down said it was built to run on low-octane gas. can anyone explain?

 

Man that could be a lot of thing's. It almost sound's like a broken motor mount? What does the noise sound like more specificley?

 

it kinda does sound like a broken motor mount...thats wat my dad is sayin...it sounds almost like if you put a hollow pingpong ball in a large room and bounce it around really loudly. i said our car broke down...the intake manifold cracked and we had to get it replaced...almost 2000 bucks...for a few days, it dosen't make any noise, even when it is floored and pushed to the limits (test by my dad and me ) but a few days later, It starts again. and it was worse than before the intake was replaced. its hard to decribe the sound