P0420 pending?

Well in a way that's good news, plus when I bought the truck at 157k miles I got a 3 ring binder of service the truck had done to it, and I've always kept up on maintenance with the truck as well. In your opinion what on the intake would you be looking for as a leak?

 

Problem is your intake consists of all your vac lines....with the brake booster itself being the biggest and hardest to detect for possible major leak....

pcv valve/groumet and its solvent vapor carrying hose is also a big vac offender.
Egr valve could be stuck open or closed...

I would look for obvious rotted lines or wallowed out ends on the lines that are no longer snug.....

I got around this by slowly replacing all mine with silicone ones that will never deteriorate, but that cost a pretty penny and took some time to get all the right sizes....

More and more I think some kind of smoke machine is becoming an essential part of working on these.....because of all the vac lines, and even the evap and fuel tank vent system can develop hard to find leaks as these age...
A lot of times, the only way to find these is to smoke em out...

$15 vacuum gauge from like Harbor Freight would also come in handy at times...
I've seen little smoke machines online as cheap as $60~$70..
and had a buddy make one out of a sun tea jar and an old soldering iron..


Even if this has nothing to do with your current situation, in time....it will...