the car runs rough after tune up
You can rule out a push rod as escort's don't use them, if you didn't blow out the crud from around the spark plugs before you removed the plugs, something may have dropped inside the combustion chamber and is stuck under a valve, if compression is low on one cylinder then that is the most probable cause, sometimes just revving the engine it up will blow it into the exhaust system if it hasn't already caused a hot spot and burnt the valve and seat, otherwise then you will have to remove the head.
You may have been unlucky and got a defective spark plug or spark plug wire set. I work at NAPA and unfortunately it does happen. HTH. -Jim
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