My 99 alero v6 3.4 just got a new head gasket installed and ive checked the coil pack replaced wires and plugs but for some reason im still getting the misfire on multiple cylinders specifically #6 what else can i do i am purchasing all new sensors today cam, crank, map, maf, and injectors other than that any suggestions?

SOURCE: My '04 Alero 6 cylinder has a #2 cylinder misfire. I have changed the plugs, ignition wires, and the coil pack. Is there any other reason this problem continues to happen?

Sure, there are LOTS more possible reasons including:

> Blown head gasket
> Burned valves
> Broken valve spring
> Collapsed valve lifter
> Bad fuel injector
> Fuel injector circuits open or shorted
> Vacuum leak at intake manifold runner
> Vacuum leak at injector O-ring
> Worn-out or broken piston rings
> Cracked piston
> Cracked cylinder head
> Worn camshaft lobe
> Defective Powertrain Control Module

To put it simply, proper diagnosis needs to be performed in order to eliminate the possibilities and get to the root of the problem so you do not end up spending your life savings on parts that your car does not need. As you have probably discovered by now, diagnosis by parts replacement can get very expensive very quickly.