Not real sure what to do here or if I'm doing this right... but i have a 88 ford f150 with a v6 300. Was driving my truck and all of a sudden it pops and backfires then shuts down.cranked it back up and it ran for 15 seconds then just died again. Then it wouldn't crank again, came out the next day and ran it around the blocked for 30 minutes and it did fine. Then an hour later, cranked it and out did the same thing.. can anyone please help me out point me in the right direction. Please