[Phil th Barrow]

Yes a new test centre is th way to go. Another test would be you go is take th oil filler cap off when its running. If it blows ya hat off your cylinders are "passing" Then as said before a compression test. Does it use oil and/or blue smoke from th exhaust??? If it does it on th over run it could be old cracked valve seals or warn valves. Start at th cheap end and never except th worst prognosis.