Got audi a6 from auction took to mechanic to diagnose told me I have low compression below 30 psi in cylinder 1 2 & 3? But engine still runs Is it a timing issue ?

 

This could be a timing issue if the exhaust or intake vales aren't closing when they are supposed to. I believe the next step would be to do a leak down test to determine where the loss of compression is occurring. I hope this car was purchased for a very low price as this could get ugly if damage has occurred from the cams not being timed properly.