Hi this is my first post.

Just bought a Astra mk4 (x17dtl GM Lump)

The turbo comes in when it feels like it, which is not that often (Once a day & for 1 gear change only!!). The car starts fine & there are no warning lights on & it's not in limp home mode & revs ok.

Been searching the forums & would just like to check with you guru's what to check & the order to check them in when i have time in the next couple of days to get under the bonnet.

EGR valve (read somewhere these are sealed??)
MAF (I know these are sealed, anyone unsealed it to clean one?)

Also the water temp sensor is knackered, But i doubt that has anything to do with it?

I dont know hardly anything about turbo engines. So any tips to help out a newbie would be great.