Originally Posted by Karma
Common Symptom: Your new conversion runs great for a few miles or a few days. Then you suddenly lose power and it keeps getting worse. Eventually you limp home.
Problem: The engine is starving for fuel. Most likely because the fuel filter is getting plugged up with animal fats.
Solution: add more heat
Or, try cold filtering your oil. It's always preferable to plug filters in the garage, instead of on the highway.
You can distinguish between plugged filters and air leaks, by how the car reacts when you switch back to diesel:
-If the car "springs" back with normal power, then your veggie filter is likely plugged
-If the car still hesitates, then it's probably air in the lines
Keep in mind, sometimes there will be air in the lines BECAUSE of a plugged filter. The engine is trying hard to draw fuel past the filter, and the increased vacuum exasperates air leaks.