Q: How to replace the air filter and PCV filter in a Pontiac Firebird?
A: The air and PCV filters should be replaced at set intervals and inspected in between. For carbureted and TBI models, the filters are in the air cleaner housing on the engine top. To replace, remove the top plate, disconnect any vacuum hoses, and lift out the filter. Check the filter by holding it up to light. If light comes through, it's fine. Clean the housing with a rag before replacing the filter. The PCV filter is also in the housing. Remove it, install a new one, and replace the retaining clip, filter, top plate, and hoses. For TPI and MPFI models, the air filter is next to the radiator. Clean the housing when replacing the filter and check the ducts for damage. Replace if needed.