!988 chevy PU. I have checked timing, replaced plugs, wirers, cap, rotor, air filter, fuel filter, removed catconverter, IAC valve, and Map sensor. there are no codes. upon starting it will run but idles high and low then dies. i removed the vacume line and capped it. it idle great but when i put in gear it will not run it acts like it is out of time really bad. any suggestions