My pickup has a 5-10 second delay when starting cold. Once the pickup reaches running temperature, it starts normal. I changed the fuel filters about 7000 miles ago. I thought I might have a bad glow plug or a weak one, so I plugged the pickup in and it started normal. Then I had the pickup tested for bad or weak glow plugs and the computer indicated nothing wrong. Any help would be greatly appreciated.

. Remove and charge both batteries. Most auto parts stores will do this for free. Your F250 requires two strong batteries.

. Use full synthetic 5W-40 heavy duty diesel engine oil. Diesel engines start much better with synthetics, plus they help save your battery, turbo, and starter motor. It makes a huge difference. Ensure the oil is up to the Full line, since it can affect fuel pressure.