If you mean the ERG valve which relates to emission, I recommend having a mechanic do it, but the valve itself is not expensive about $50.00. I let this problem lag on and it blew a cap called a diverter valve that has something to do with vacuum, dont wait like I did.
The 2003 Chevrolet Malibu PCM valve can be found on the firewall in the engine compartment. The PCM valve will be on the passenger side of the firewall.
You did not say what size engine but in most cases the PCV valve is in the valve cover.
The 1999 Chevy Malibu with the 2.4 engine does not use a PVC valve. Instead the system uses an oil/air separator that can clog up and cause the same symptoms.
on 2000 3.1 it is on passengers side between engine and firewall,about 1 foot down..
Trouble code P0401 means: Insufficient EGR Flow Detected Replace the EGR valve
NO it can not as there is a check valve located in the filler neck.
It is just below the lower radiator hose.
Did this to my 98 Malibu v6, the low pressure valve is on line beside fire wall behind engine, it has blue protective cap on it. high pressure valve you would not use has red cap on it located beside radiator/condenser. You don't say what year your Malibu is so this may not apply to you if your unit uses the R12 refrigerant.
It is on the low side line as it runs across the firewall under the hood, between the engine and the firewall, generally closer to the passenger side of the vehicle.
no the egr valve has a big effect on the engine,it is controlled by the pcm.
Valve cover
If the 4.3 Chevrolet engine is new enough to have an EGR valve it would be located in the exhaust pipe where it meets the engine. Some vehicles did not start using this device until after 2000.