fuck antilag, sounds like you need antibag

the turbo would have chopped the bag to smithereens, going through the combustion chamber would have melted it, not sure there is much you can do now besides strip the motor or leave it & see how you go, might all just melt away after a good thrashing

similar story here:
Plastic bag got sucked into 7.3 Powerstroke turbo? - Yahoo! Answers