This car was a daily driver up till this happened 3 weeks ago. About 3 weeks ago it overheated on the highway after a radiator hose blew, and after that incident it wouldn't start, after getting a new head gasket put in I am still having some problems. The car starts now, but when I give it gas it won't hold the rpms, If I put the gaaccelerator down it jumps up, but even with the accelerator to the floor , the rpms drop back down and it wants to stall. If I don't give it asny gas it will sit there and idle at low rpms fine. It is also backfiring a little when it drops from the high rpms and I can't tell if the turbo is spooling up right but the boost gage really seems to lag behind the rpms. Is it possible I messed up the turbo when it overheated ? Any help would be greatly appreciated. I would like to get it running right before I put in a new radiator. Thanks for any help.

swap the injector plugs, you may have them backwards.