Originally Posted by JackGTA
could they have been having a bit of fun with the car while it was in?
Not un heard of but very rare nowadays
i'd forget the stem seals for now....
A compression test is not going to be cheap, expect a couple of hours labour (by the time they have removed the intake, head cover, coil packs and plugs)
If you have a friend in the know, it would be an advantage...
Best not to speculate too much at this point as it could cost £150 to and upwards of thousands to put right
Start cheap, then work at the expensive later, a few quid well spent on a proper diagnosis could save you alot of ££ in the long run...
(AND THATS WHAT IAM HOPING FOR YOU!!)
Good luck
