I am having trouble getting my 98 Xpress 300 to turnover and when it does it runs for a couple of minutes and dies. The main problem seems to be that the spark plug is not constantly sparking because I take it out of the engine and see no spark when I turn it over. When it does start it dies as if the spark has died on me. I checked the celenoid by bypassing it and the same problem occurs. Any idea of what could be wrong?