I purchased a new GMC Envoy in 2005 from the dealer. Noticed it didn't have the power it should have within several years of owning it. Took it to the dealer for inspection and they claim they couldn't find anything wrong. Found out from my brother, who's an attorney, that a former GM dealer shop manager says GM knew about faulty cylinders in their vehicles but refused to issue a recall to repair due to cost. I took that information to the dealer and they were shocked and fixed it for free. Never buying a GM vehicle again!