The hole in the throttle body screen..(not a MAF screen)
will basically effect the idle.. I would replace it asap as you don't want it collapsing/deteriorating and ending up in the motor. It designed to direct the flow of air to aid in acceleration as well as fuel economy. As well as aideing in directing air flow thus resulting in a smoother idle.

 

I didnt know that screen came off...the one behind the rubber connector?

 

my eng idles fine,but when I sprayed carb cleaner at the base of the egr valve the motor changed idle and almost wanted to stall..is that a sealed unit? I remember older cars we used to block off the port there...

 

There is a vacuum line that runs to the EGR. If there is a leak, which your brake cleaner spray seemed to indicate, that would be where I would look. And if you do have a leak, aka more air getting into the combustion chamber, then you could get a Lean mix code. Question though, is that the only code your getting?
It could also be that since you removed/cleaned out your CAT, now the exhaust is flowing too fast for the O2 sensor to get a good reading. I'm not sure if this will work but try blocking one of your mufflers. That should cause more pressure in the system and the light to go off. Logically at least! There are many things, as previously listed, that will cause that Lean code. Since yours started when you emptied your cat, i would start looking there. And work back from there to your intake and fuel. The leak in the EGR is a problem that needs to be addressed and I would take care of that Fisrt. Then go back to the cat if the code remains active.

 

Yes. you need the o-ring. Put one in, properly reassemble and install. Your problem will be gone.

 

When you replaced your PCV valve did you replace your MAP sensor as well? It sits on top of the PCV. There sh old have been a new O-Ring on the new PCV. Same of the MAP sensor. IMO if you replace one you should replace the other because in our configuration the work together as a single unit!

 

Unless he is getting a code indicating a problem with the MAP there is no need to replace it. To do so is just a waste of money.

 

03SSLS Is rightt. The MAP sensor does not wear the same as the PCV because there are no moving parts in it. But it is cheep, I paid about $12 for it. But because the PCV has a hole in the top too so the MAP can take its readings it gets the same dirt and oil in it as the PCV. As I said, it is only my opinion that they both be changed as a set.
Think about it this way, your drivers side strut is bad, you replace both, mostly so the car rides the same on both sides, they work together. These do the same. And like I said, this is just my opinion. I'm off center any ways. I mean, while the rest of you are lowering your Monte's I raised the back of mine.

 

If your dome light burned out would you replace your map, courtesy and trunk light also? If you replaced your shifter handle would you replace the shifter assembly also? If you got a hole in your sock would you buy a new pair of shoes? Don't get frustrated or upset - I'm just yanking on your chain a bit.


The OP stated that he did not get an o ring with the new pcv. Since an o ring was not installed unmetered air (vacuum leak) is entering the engine and causing his problem. Installing an o ring should resolve the problem.

 

Not taking anything personal. We are different people with different opinions.
I agree that a PCV without an "O" ring will cause a vacuum leak.
03SSLE, you and I always seem to but heads but that's ok. That means the member who started the post will get good, helpful and complete info. And also that I might, as I have in the past, learn something about my Monte, from you!