HAUS

when my car is started and running it rattles like you wouldnt believe. sounds like its coming from under the hood. i check the heat shields and they seem to be alright. any ideas what this could be.

e40water

Just a guess maybe youre exhaust is loose, Sometimes they make noise, Maybe youre timing might need to be checked, Or what kind of fuel are you running?

HAUS

maybe the exhaust is loose. my best friend like to drive my car and we live in a town that the road are in really bad shape and keeps hittying the exhaust on speed bumps and pot holes. im running regular. sounds like the rattling might be coming from the alternator or tentioner pully. some where around that area. i know that its not coming from inside the engine.

mustang8719

Some times the cat converters will break apart internaly and cause a rattling noise i had the same thing happen to me after for replaced mine under a recall then they gave me another set try to tap on the cats with a rubber mallet and see if they make noise

mustang86cars

If the noise if from under the hood maybe the smog pump is going bad, I heard of this once before.

e40water

Well my exhaust heat shields make these weird chalk board with finger nail screech sounds, Damn I hate that sound, Lucky for me its not that loud.

HAUS

mustang86cars where is the smog pump at on a 1992 lx 5.0. if you look at the car from the front it sounds like its coming from the left side where the passenger side would be.

roundman

that's where the smog pump is, below the alternator.
when you say rattling, do you mean it is shaking back and forth or is it making noises?

HAUS

it makes noises

roundman

be a little more descriptive of the noises. does it do it at idle or at speeds above idle?