Just to add a couple cents to the WVO discussion...I am in the middle of replacing my injection pump due to WVO related problems. My Bosch shop told me that the innards of my pump were varnished and subsequently pitted beyond repair by vegetable oil. The kit was installed by the previous owner and many miles were put on the car using WVO. In my opinion, the biodiesel route would be better. It can be done in a garage as well.

A little more work now on the fuel may save you from large (injection pump large!) repair bills later.

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1987 300TDT ~264,000 miles