My 2001 Montana van turns over but won't start. Was running I shut it off to go into store. when I came out it would not run . I left it parked and went back the next day and it started so I took it home. A few days later I was driving and it started chugging then stalled out. I can hear the fuel pump ok. spark plugs are new, new engine and trans. I know I can have the computer scanned, looking for other ideas. Engine light does not blink, just stayed on, when trying to get code that way, (key in, turn on, of, on, of, on within 5 secs).