my car is making weird noises its a 91 LS with 125,000 miles.
1) when i am at low rpms, im talking like 1500 the car sounds like its gurgling, this only happens when the car is moving and it lasts from 1500-2500
2)the second noise happens anytime the engine is at 3000-4000 rpms and it sounds like metal is scraping, i thought it was my cat so i changed it with a high flow and both noises are still going on. i checked the heat shield bolts and everything is tight.

any ideas?

 

where is the noises coming from? underneath the car? how does the noise sound like? is it a squeaking noise? maybe its your belts..... whens the last time you got a tune up? need more info.... or go to your mechanic and get it checked out!

 

no both of the noises are rattling noises comming from under the car, not hte engine. the first one sounds like a bolt in a can with water in it... yeah and the second one sounds like a heatshiled vibrating but its not... kinda hard to explain

 

i had the same problem, but when i got my exedy clutch and fly wheel put in it went away mine was happening between 2k and 3k. if you can just lift the car up and check the tightness on all of the bolts you see

 

try to check cat converters shield..