I have noticed my intake manifold pressure (boost) has been creeping up on normal driving cruise and I am seeing some black tailpipe smoke on even gentle acceleration (black smoke is fuel).
I decided today's drive would be spirited to clean out the built up carbon from the turbocharger and wastegate mechanism. TDIs are known for fouling wastegates from long durations of low or no boost driving.
So I drove to work at 70mph and did some aggressive acceleration on onramps. Not floored but up to 8 - 9 psi of boost. I was expecting to see a huge mpg drop on the one way commute, but I got 57.4 mpg trip commute to work (only a 10% drop from yesterday)
That was unexpected. I only got 65 mpg yesterday driving very conservative with max coasting and a max speed of 60 mph.
So, either my Scan Gauge II is still not reading fuel usage accurately, or my granny driving, and super slow acceleration, and general lugging the motor in 5th at 51-55 mph on the big hills is not conducive to getting the best mileage. I may be over fueling the motor running it at too low of rpm. I try to not cruise below 1,500 rpms or it shudders.
I am happy with achieving 57 mpg with normal driving. Can't complain about that. I will try some normal acceleration and keep it at 60 mph max and see if that increases my daily mileage.
The good news is that none of my cheesy coroplast aero mods fell off at 72 mph.
and I am getting real close to my goal of achieving 60 mpg at 70 mph steady driving.