Hello from Atlanta, GA.  For 2+ years my rebuilt air cooled has gotten 18 MPG.  We do all our own maintenance per Bentley.  In 11/02 passed emissions.  However, in last month mileage has dropped to 13 MPG.  I have perfect timing and dwell, Idle RPM increased to 1100 when mileage went down in 1/03.  I adjusted idle to specs---875 RPM.  I am running original injectors, newer thermo time switch and  cold start valve.  I also notice a very slight jerky acceleration, together with equal black soot (not oily) deposit on all four of my spark plugs and my tail pipe.  The van does start first time every time and runs OK as my daily driver.

Suggestions on where to start?  New injectors, new/rebuilt airbox......???  Thanks!

Regards,

Mike and Christina Nichols
2--'81's