I purchased an 06 mini cooper S from a dealer and got the check engine light/DSC light 3 days after buying it. I took the car to autozone and found a P301 code misfire cyl number 1. I did a quick compression check and found number one was low. Took the car to dealer and they had the same diagnosis. It's not a mini dealer so they sent the car to a shop that is familiar with the mini and they to ran a scan and compression check. The dealer and the repair shop came up with 110 140 150 150. They decided to pull the head but couldn't get the aftermarket warranty to warranty it due to pre existing. The dealer has a 30 day 1000 mile warranty on all used vehicles and they didn't want to pay for the head to come off. It was later found that the fuel pressure regulator was faulty and needed replaced. The repair shop thought this could of caused the SES light and low compression by washing down the cylinder. The shop replaced the FPR and ran a wet compression check. cylinder 1 came up to normal. They then drove car for 7 miles and repeated the compression check and cyl 1 had dropped back down to 115. They recommended to my dealer the car needs to be driven more and that might bring up the compression. The dealer took the car did a compression check and came up with 110. They then drove the car 150 miles and did another check and now at 120. they tell me to come get the car as it is fixed. The minimum is 130 so it is not fixed. I'm trying to get them to take it back but they refuse and tell me I need to come get it as they complied with there warranty and made the check engine light go away. I'm looking into a lawsuit and need to get official mini documentation as to what the cooper S compression range is and what compression difference is allowed. Thank you for any insight.

 

Not sure what help you are looking for, it sounds like you have it under control. I certainly wouldn't accept that as a repair.