On a recent long highway drive, I continued to slowly loose power and fuel economy. When I got to my destination, I found that I needed three new fuel injectors. The car ran fine on the way home. Soon after returning home, I started to loose power again and the MPG’s has gone from the low thirties toward the teens. Do NOT know what the heck if going on. I have replaced the fuel filter, but not the fuel pump. When I put an octane boost in it seems to run better.
Help!
Who determined that you needed three new injectors?
And how did they arrive at that conclusion?
Have your mechanic hook up the scanner, check for DTCs, check fuel pressure.
Is the check engine light on?
Any other symptoms? Better on short drives? This in addition to mileage and @db4690 's questions.
You may have got a bad tank of gas somewhere on the first trip. A mechanic could drain the tank and look for water or debris in the gas. If contamination is found, you may need to have the entire fuel system – filter, pump, pump inlet screen, tank, lines, fuel pressure regulator, and injectors — cleaned or replaced.