Valve seats (components in the cylinder head that help seal the valve) can fall out. When this happens, it causes rough running and creates noise. Replacement of the cylinder head is commonly required to fix this problem.Google+
Car Problem Reports
Mercury Tracer Valve Seats on Cylinder Head May Fall Out and Cause Rough Running/Noise
Mercury Tracer Problem
Engines Affected: 1.8L 4 Cylinder, 2.0L 4 Cylinder
Average Mileage: 121,000 mi (60,000 mi - 229,000 mi)
Visitor, 1997 Mercury Tracer, 2.0L 4 Cylinder, 60,000 mi
No solution yet but ill probably try to buy a rebuilt cylinder head with improved valve seating to prevent further issues with this. Also, make sure all components to the cooling system are 100% because its often the overheating that causes the steel valve guide seat to slip out from the more rapidly heating/expanding aluminum cylinder head.
Visitor, 1995 Mercury Tracer, 1.8L 4 Cylinder, 74,000 mi
I just bought this 1995 Mercury Tracer and after day 2 all of a sudden it has rough idle & hard start also the speedometer does not work.