thanks before i did the head gasket about a month 1/2 ago at times it would only be code P0420 Error Code: Catalyst System Efficiency Below Threshold Bank 2. usually that means cat is on its way out. since the head gasket no more code p0420. but the new code everything was new gaskets seals throttle body elbow plugs coils.only had this truck since may/2014 previous owner really did a job on f----ing it up.well the intake bolts took 4 more turns on the bolts.more driving to do.do you think this scanner is good=http://www.ebay.com/itm/USA-Shipping-Creator-C110-V3-6-BMW-Trouble-Code-Reader-Diagnostic-Scanner-/111400452001?hash=item19effbffa1&item=111400452001 &pt=Motors_Automotive_Tools&vxp=mtr
its for bmw only.??

ok here is more info while the truck running and the scanner on LT FTRM 2%=3.1
it never change while running for 20 minutes cooloant temp at 210 here are pix of what the o2 are doing does it look like down stream sensors are 1/2 working even though they are new.???thanks

Have you run any fuel injector cleaner? If you have a partially plugged injector, it may resolve the problem w/o opening anything up.