'93 W250. I just put on a new lift pump. Got it all primed up and she started with a little cough and sneeze but other than that she ran fine. I drove her down the highway for about 10 miles, and stopped to get fuel. Went to start back up and it wouldnt start, turned over but wouldnt fire off. Soundt to me like its losing prime, but how? Does it sound like im sucking air? BTW, today is the first time in about 7 months this truck has been started. Thanks for any help