Have you asked any of those shops what they have specifically done? Sounds like a CPS or O2 sensor to me but no way to be certain without hooking it up to scanner to see what trouble codes come up.

1996-newer are OBD-II so a scanner will need to be able to read OBD-II codes, obviously.

Chris


1983 CJ7 with 1.21 giga-watts and a supercharged flux-capacitor