Wierd car shit

[prodsm]

90 tsi awd 5 speed

while my car is at idle, it does not make a continuous sound from the engine, it kind of sounds loud then soft then loud then soft. The car seems to run fine when i drive, just at idle it sounds wierd.

Problems i know i have:
Cracked Exhaust manny
small oil leak in turbo

Help

thanks

 

[ABK]

well if you got a cracked exhaust matifold it's prolly fouling with your turbo, or with your computer, I would get the fixed first then try to figure out the rest.