I have 1988 E - 250 Van with 5.8 EFI engin. I am having problems with my fuel managment system. It started running rich and would have a high idle for about 5 seconds and be fine. The last time I started it up the engin flooded and filled the cylnders with fuel, so bad that It hydrolic the pistons and fuel ended up in the oil. I have replaced the map sensor, oxy sensor and found loose vac line, but it still happens. Any ideas?

 

Check your fuel pressure regulator. Pull the vacuum line to it and see if there's gas in there, which would indicate a ruptured diaphram in the regulator.