Had check engine light come on with code p0420. I have 138,000 miles on the truck. Bought the truck used. Replaced spark plugs with new sp515 motorcraft and cleared code. Ran fine for a couple days and then the check engine light came on again. Code p0430 this time. Once it warms up it does have the common ticking noise. Could the cam phasers, timing chains and tensioners be causing the problem? Where is the best and most economical place to get all of these parts and what other parts would be needed to do this job. i.e. gaskets etc. I know that both of these codes indicate "Catalyst system efficiency below threshold" and p0420 is for bank 1 and p0430 is for bank 2. Any help would be great! Thanks in advance!!

 

nobody has any input on this?

 

These are codes that are very commonly discussed.

Plug them into the SEARCH tool for previous discussions.

 

Most P0420 and P0430 codes have to do with actually bad cats.
IF the exhaust has been messed with, X over piped removed or the two rear O2 sensors removed, this could be the issues.

Check for a vacuum leaks.

Most likely not the timing system, but if your phasers are original, time for a replacement. Might as well do the entire system while you have it apart because the guides and tensioners will be going bad around 200K.
Rockauto.com is the cheapest, but I like the OE Phasers so I pick them up from a discount dealer website. Only gasket you need is the front cover.
You'll need a power steering pump pulley puller (Try to say that 10 times fast).

 

With 138K on it I would pony up for new lash adjuster and inspect the rocker arms while I had the covers off. Also make sure to pull the VCT solenoid valve bodies off the heads and clean them and replace the the gasket between them and the head. Any leak in the VCT system will cause oil pressure issues and therefore bad VCT system functionality.