That's what it's called!! Couldn't remember

The back valve (By the firewall) Is a PCV valve, the front one is a CCV. Best to replace them both, since they are emissions related.

 

I just changed that sme ccv today, I bought it at O'Reillys off the shelf it says for 1999-91 jeep cherokee w/ 4.0 you can also take off the valve cover and clean it with a paper clip theres a small hole that gets plugged up. If you try to pull it out it will most likely break ( ask how I know ) it is 14 years old and plastic. took me about a 1 1/2 hours to replace along with a new valve cover gasket.

 

Picked up the rear CCV valve for $7.00 . I thought only the Jeep hats were less than $20.00 at the dealer.
I'm thinking of running seafoam through the intake and in the gas tank before I change the O2. Would I need to make sure to go through the whole seafoamed tank and refilling with fresh gas before getting the smog checked again?

 

Haha told you it wouldn't be all that expensive. As far as Seafoam, no you wouldn't have to go through the whole tank. At least I wouldn't think it would have much of an effect. You may want a second opinion though.

 

Previously after I cleared the codes and drove around the block, the scanner wouldn't show any codes. But after taking on the freeway it go back to the lean air/fuel at the O2. Now I seafoamed the intake, changed the O2 sensor, fuel filter, air filter and spark plugs. Now after a freeway drive I'm not throwing any codes. I guess I'll get the smog checked again tomorrow and see if it helped.

 

Update: Well my XJ passed smog today. The new O2 sensor and running seafoam through the intake really cleaned up my emissions. Time to move to South Lake Tahoe so I won't have to worry about smogs ever again.