2001 Wrangler with 4.0 (auto trans). Engine cranks but will not start. I tried to pull codes but PCM will not communicate with my code reader. Check engine light is on as well as low fuel light. Gas will shoot out when I press valve on fuel rail. Oil pressure gauge was not working properly prior to starting problem - would read very low at idle but normal when engine revved. Have replaced the sending unit. I disconnected the battery to try to reset PCM but no change. Any ideas as to what might be the problem?