Mileage Issues (ALH, all major steps taken)

So, background on the car and its current maintenance

2001 Golf TDI
150000 kms
Automatic

The car currently gets an average of 30-33 mpg (~700 kms per full vented tank)

Steps taken to increase mileage

1) Timing belt done (timing is slightly advanced but within spec)
2) New fuel filter, air filters
3) New OEM nozzles
4) Brakes do not drag
5) tires inflated to 90% of max
6) Snow screen is clean
7) Replaced all vacuum lines
8) thermostat is okay, tested with thermometer
9) intake is clean

Driving habits are extremely good. No stomping on the pedal what so ever.

Don't know what else it could be.

Testing the MAF, i unplugged it and the car seems the same. The only thing i notice is the lack of power above 100 km/h. Car struggles to get past 110. But the mileage seems correct. It gets 45 mpg with it unplugged based on the scan guage. Is the MAF slowly failing.

With the MAF plugged in, at 60 km/h in 4th gear, the scan guage reads around 55mpg. but once you get up to 100 km.h, its sitting around 30. meaning if i was doing only highway driving, i would get 30 mpgs. something is wrong.

What is the performance like when the MAF is plugged in (i.e., does it also struggle to get over 110?).

Is the car 'chipped'?

Personally I find that the MAF needs to be replaced around 130-150k miles, you're not there yet but getting close to that.

Car is not chipped. With the maf plugged in, there is a little difference in acceleration. not a whole lot. The car does go over 110 with it plugged in but its not that much faster.

i should also say, the IQ is set to 5 with the stock nozzles

Yeah, it does sound a lot like the MAF is the culprit. But note that there are other things which look the same - for an example, a cut in the air duct downstream of the MAF will have the same effect.

hmm, there arent any cuts in the short pipe between the maf and the intake?

what else could be wrong

me too

I also have had bad milage around 35 mpg,
I had my mechanic replace my vacum lines before the start of summer, I am now wondering if the vac lines might not have been done properly, how would I know?

bump anything?

I'm VAG com equipped in Stoney Creek, I could come out and run some scans on your car if you want. I do charge a fee, but its nominal compared to dealer charges, and I come to you. It'll only take an hour or so, I'll do an autoscan of the car then do some data logging and see if I can come up with anything. PM me if interested.