Your EGR might be clean, but it's not sending proper signal to the ECM. The pre 1998 3.2L uses a differential pressure transducer to send EGR signals to the computer. To troubleshoot, locate two signal tubes from the EGR, that will lead you to the transducer. It will have two tubes/hoses/pipes & a wire connector. Your truck will have 4 oxygen sensors if equipped with automatic. 3 if standard trans.
G/luck
Joel