Originally Posted by intrepidagent

This is something that I should have done about a year ago. I have a 85.5 NA with approx 80K miles. I drove the tank down to near empty and when I filled it up I thought it would be a good opportunity to throw in a bottle of Chevron FI Cleaner. Big mistake. After about 1 hour of driving the engine was coughing, sputtering and felt like it was running on 2 or 3 cylinders at times. Replaced the fuel filter. No difference. Replaced the fuel pump and the car ran flawlessly. Apparently I stirred up the ancient evil demons in the tank who then took vengence on the aformentioned components. OOPS!