Chevrolet Repair: Service Engine Soon light, saturn misfire, saturn

Question
I took my car Saturn 2001 in for diagnostic, and was told that I needed to replace fuel injector and secondary injector.  Afterwards the Gerry Lane in Baton Rouge dealership called to say that when the repairman test drove the car, the intake gasket was blown, and that was another $300 or more.  Is this fair, or even possible?  I am inclined to think that this was the major problem all alone.

Please Help

Answer
To be fair I would have to know more . What code did they pull ?
what other symptoms that caused you to take the car in ?

That being said , it is very possible that they miss diagnosed it
the first time.

These cars have a common problem with intake manifold leaks around
the #1 cylinder runner. usually will cause a p0300 code or p0301
(random misfire or misfire #1 cylinder) and possibly a higher than
normal idle.