If you pull the inlet tube off, hold the throttle blade open and look at it.
If it's black, it needs to have the blade and throat area cleaned.
Spray it with carb cleaner, then use a rag to remove all the black crap in the throat area, and get the backside of the blade; Especially the edges.
Be careful not to bend it, lol.
The black crap where it closes will cause off idle problems, in that transition region; I guess if it's bad enough, it could make it not idle.
Don't indiscriminately spray a bunch of carb cleaner down in there; you'll wash the black crap in the intake into the cylinders as a glob, and that's not good.
This being a 97, you could do a PI intake swap, and thoroughly clean the throttle body; eventually the EGR passages muck up.
It's a lot of hassle to clean out the intake/TB, so having a reason to unbolt it makes it easier.
Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.
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