Heres the story. I have an 84 300SD that I do not drive a lot. I have read about algae forming in diesel fuel over time. I put an extra filter in line before the see through pre filter thinking it would help filter any algae and that extra filtering would be good. It was a little canister filter that I picked up at Auto Zone. It had been on there over a year and probably 2000 or 3000 miles. All at once the car felt like an injector on one cylinder was bad and the engine was losing power badly. I started looking on line at injectors, injector nozzles and how to clean them and was very close to pulling some injectors. Well, I took the see through prefilter and the filter I added off and I could not blow through the canister style filter I had added. I changed the see through prefilter, cranked it and it was back to running like it should.