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..., it looks like it has 2 vacuum lines connected to it and a electrical connection right next to the vacuum connections. Am I looking at the right thing? If so, which vacuum line do I disconnect to test it?
It is againt the firewall but on the drivers side of the engine. Also looks like it is held on by a bracket that is bolted on with hex head bolts.
Again, it is a 3.2 V6,
sounds like you are talking about the egr valve.
the fuel pressure regulator has two fuel hoses,and attaches to the fuel rail, the thing that supplies the fuel injectors. and it has a vacuum attachment as well,

since you apparently don't have a workshop manual, go to the isuzu online parts site, and find the parts illustration.
www.myisuzuparts.com

//bc

1992 sohc trooper 3.2l v6 automatic . . . as is

i love a good intermittent electrical challenge. . .especially when it's someone else's.