Well my car did this due to a leaky fuel injector seal and made some of the same noise yours is and it turned out to be a bent conecting rod along with a washed out exhaust valve.Hope that this is not what happed to yours I was able to fix mine with some help and it still ran me like 900.but I did some other things to it as well when in there.

Good luck

R96SE

Fully Modded Duratech,love my indaglows,lowered,two tone paint,short shifter for auto,custom front bumber pre 98,3 inch custom exhaust.Third place winner at 03 all ford nats: Lets go for a fun run soon !!!