I'm trying to retrieve any codes on my 91 4R 3.0 in the quest to fix my smog troubles(high hydrocarbons).I followed the manual:warm engine,neutral,accessories off,jumpered wires on diagnostic plug.When I turn the key to on,the check engine light just flashes non-stop with no delays.The check engine light was not on when driving it but I just wanted to see if anything was there.According to the manual,it should flash one time every few seconds to indicate there are no codes.Please help.