The normal problem with that engine is the decomposition of the plastic
plenum. This is a common and well known problem with that engine,
and the price he quoted sort of fits the typical expected.
The coolant gets into the cylinder, and can cause hydraulic lock.
If so, an improved plenum can be purchased from NAPA for about $150.
Installation might be as low as $100-$200, if you shop around.
Maybe yours is something else.
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