everytime i shift the truck from park or neutral to drive or reverse, the truck will shut off completely. no bad die out, just simply shuts off as though you turned it off with the key. Replaced, fuel pump and filter, distributor-cap- and rotor. map sensor, checked all emissions lines and valves, egr valve. everything seems fine. changed gaskets on throttle body. cleaned throttle body. spark plugs. going to check timing today, may have to redo distributor, idles fine. timing doesnt line up, but when i line up timing to tdc by moving distributor, it dies out. any suggestions???