Not all engines had them. Look on the emissions sticker under the hood. That will show its location if there is one.

That would be all fine and good except for when I bought the car it had been hit by a deer so the hood was crunched. I owned a 1987 Plymouth Sundance that was slowly dying. I took the hood off the Sundance and Put it on the Shadow, so unfortunately the actual hood for the car went to the junk yard with the old car.

The only '92 service manual I have is for the minivans but usually the engines are the same on all models. For those with an EGR valve, it is sitting on top of the passenger side of the exhaust manifold, behind the engine. There will be a black plastic disc on top with a vacuum hose going to it. That's the transducer that would be shown on the vacuum diagram.

You can also look on the stickers on cars in the salvage yard.