I have a 2001 F-250 power stroke that is very hard starting in weather below 30 degrees. It coughs and coughs and cuts out. Sometimes it takes 15 to 20 tries before it smooths out. I have changed the glow plug relay switch twice in 6 months. The last one went in 2 days ago. When I keep the engine heater plugged in, it starts fine. Looking for any information that I may try or give to a mechanic to fix this problem. It's become very frustrating along with being inconvenient. Any help would be much appreciated. Other than that I love this truck and the 7.3 PS. Thanks, mookie250.:confused:

. Ensure both batteries are fully charged.
. Clean battery terminals and connectors.
. Check glow plugs.
. Use synthetic HDEO. If you install a by-pass filter, many diesel engines can go 60,000 miles+ between changes, provided you get regular Used Oil Analysis (UOA) done.
. Add diesel fuel additive.
. Purge any water from fuel system and change fuel filter regularly.