I've got the 5.9 gas engine and it's throwing codes:
P0442- evap emissions leak detected (small)
P0455- evap emissions leak detected (large)
P1195- o2 sensor slow during catalyst monitor

I know the small leak could be something as simple as a new gas cap but I've replaced that already. But the large leak, I have no idea.
I assume a new o2 sensor would take care of the other code.......?

How can I try to find and fix these leaks myself?
Thanks

 

If you want to find the Vacuum Leak yourself, get a can of brake cleaner spray and in small shots w/ the engine running spray it around your intake manifold. If the engine shudders/sputters/etc or stalls then you've found your leak.

If you want to find it without risking hurting yourself or getting brake cleaner on a sensor and damaging it, take it to a shop that can perform a "smoke test" on the intake & EGR system...

My bet is the "large" leak code is either coming from a crack or poor seal on your intake manifold or a bad/damaged EGR System Air Pump (aka EVAP Pump)...

The O2 sensor problem is likely due to either a Bad O2 Sensor, but I'm betting it is directly related to your EVAP Pump being busted, as that can also cause that code to show up.

Good Luck and Please post up the solution when you find it!

 

I'll give those ideas a shot. But first I've gotta replace the fuel pump, it just went out.
Would all these evap problems hinder fuel economy?

 

Yes... but dso can a bad fuel pump...