Then again, the valves can wear out of round, giving you intermittant sealing and intermittant miss from no compression, backfires up the intake, etc.

Replace them if they are frozen, they are cheap.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!