Originally Posted by dorydorydriftin

had the same issue on my ka, started as a small noice did'nt really seem to be a huge issue, drove it about anouther 100 miles and the noice turned into a knock from my rod. Guessing the scratching kind of rattling noice was a wear/warped/and disformation in the rod and then after time the repeated heatings of the rod it eventually broke....
A ton of stuff can cause a rattle, seen case's where it was just a loose bolt on the exhaust, could be someting significant like a main bearing.. I'd suggest ( you work at carquest ) scan the car and see if any trouble codes are being thrown at you, also if you feel up to it maybe hit a compression check on the motor.