If the Catalytic Converters go bad, will there always be codes thrown.....?? Brief history, just did the Phasers, chains, etc.....starts and runs great. Until you put it in gear. Engine still runs fine, but absolutely no power.......??? undriveable.....Vehicle 2006 F150 Lariat, automatic, RWD.......175K

 

was the converter plugged BEFORE you did the phasers ? My first guess would be that you have the timing chains off a tooth or two.

 

Upon initial startup after doing the phasers, etc......codes were referencing cam position sensors....went back in and corrected for being off a tooth.......Now it starts and runs fine, until put under a load. No codes at all.....!! I'm thinking that the cats may have been on their way out prior to doing the front end.

I just hate to throw any money at it without a reasonable expectation of success.

I'm old school, never replaced any parts till we knew they were bad.

 

An old school mechanic's vacuum gauge will reveal any restriction in the exhaust in about 30 seconds.

 

Take the CAT loose from the exhaust pipe and run a mile down the road and back to test... You will be loud and get other codes, but will be a good restriction test.

 

Yes there will be. It might take a couple of start up and shutdowns for the CEL to turn on because some codes first set as pending and later escalate to an actual trouble code where the CEL will turn on.