Just because replacing the head gasket is a nasty job does not mean the engine is a total loss. Pretty early though, most of these happen after 100K. I bet the previous owner used the cheapest gasoline he could find. You will also find that the PCV system is probably in need of cleaning - depending on what the mechanic did when he replaced the gasket.

If the price is 'good' and the car has the features you want, the electrics all work, it has passed inspection, then you should be good to go. Do not let the number of miles inflate the price! A car seldom 'driven' is worse than a car with a bunch of well maintained miles. The timing belt/tensioner/pump is a plus, you should be good for another 90K miles.

Yes, check the electronic throttle module at the throttle body. It should have a yellow sticker, white is bad. When the ETM fails, yours can be repaired by www.xemodex.com for around $500, stay away from the dealer for that one.

Klaus
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My advice is free, so you got what you paid for...