I looked hand over fist and could not find it. So I called a mechanic and he explained that some of the 1991 Ford Explorers do not have it. Mine does not.
the PCV valve is located on the valve cover of a 1991 Regal Custom. It is plugged in and can be easily changed.
The PVC valve for a 1991 Skylark should be located on the top of the valve cover. It is a plug in type, twist and pull to remove.
on the valve cover
The 1991 Geo Metro EGR valve can be located on the air cleaner housing. The valve will be on the back of the housing.
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The 1991 Acura Integra idle air control valve can be found on the firewall. The valve will be on the drivers side of the firewall.
I have a 5.8L in my 1990 and it is located behind the intake on the passenger side. Right by the valve cover.
For the 305 (LO3), the PCV valve is located on the driver's side valve cover. It's held in place with a rubber grommet.
it is located on the firewall under the brake booster
The transmission dipstick for the 1991 Chevrolet Caprice is located on the side of the transmission. It will be behind a valve cover.
The idle air control valve is located on the throttle body, and the EGR valve is located on the intake manifold.
A 1991 Ford Explorer XLT , that has the 4.0 liter Over Head Valve , V6 engine is rated at ( 155 horsepower ) I believe