I have tuned it up. ripped of the heat shield. disconnected the a.c. and when in drive, foot on the brake i get a wicked rattle. any ideas?

 

What condition are your brakes in? If you had a really worn pad, it could shake around in the caliper (it would have to be completely toasted though.) Do any of your rotors looked scored?

You could also check to make sure your master/slave cylinders are still tightly attached to the firewall. Bolts can loosen over time.

 

When it is making the rattle noise, try pulling the hood release lever and see if it stops. Really common for the hood latch to rattle as the rubber bumpers in the front corners start to collapse over time.

 

thanks babyhuey your right

 

Thought that might be the problem. You might be able to crank the rubber bumpers up by turning them counterclockwise a turn which will raise them by 1/4" or so. If they do not adjust then just stick a piece of foam tape to the hood where they contact the bumpers and will do the same thing. Sorry but I forget when Mazda made the bumper supports adjustable.