Help with mileage

My kids 89 diesel jetta mileage is down to 35 MPG. I've installed new injectors, no difference, Reset timing using indictor , No inprovement. It kind of feel like I've got to much Back Pressure as I rev thro the gears, How do I check this on a diesel, any other help?

Reply to
rt
Loading thread data ...

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.