ok i went by to pick up my truck today after head replacement (this makes the 10th week they have had it) and they said that they had it running and shut it off and it wnt start back ? they said that it will start with spray but not on its own. it will start after pressure gets built up above 500 rpms and then they spray ? what could be the problem ? they talking like an injector may b bad ? but my thing is that the truck ran just fine and started up great b4 i took it to them ? and im on a strict limit for parts and labor (for now) and i esp dnt wanna buy a injector . but any suggestions ?