Mpg dropping 06 Jetta dsg...

On our 06 Jetta DSG with 200k on it. The mpg's have dropped from 42 to 38. GPS verified multi tank verification miles driven/ gallons filled. We have a Malone 1.5 tune but no other mods. Is this normal or should I start to look for issues?
Do fuel injectors need replacing at some point? (That made a huge improvement in my 01 Beetle)
Thanks,
Hip

What would be a benefit to others, would first be some historical data as to what was the last mileage on your car when you got a normal 42 mi/gal and if or how often you use a fuel additive. I have not seen a lot of data as to mileage versus deterioration of injectors on an 06 and your thread may give some good data in this regard. Do you notice any other symptoms such as black smoke and under what conditions.

I have hot used any fuel additive this year. about 5000 miles ago( aprox 3months) was the last time it got 40. It made a 7mpg difference when I replaced my injectors in the Beetle(T4's or something like that), but maybe that was not the norm.

Please clarify... Your bio references a new cam. I assume in the subject car? If so, then it might be of some profit to check the injector lash as your cam pressurizes the injectors.

First up, though, are filters. Unless they're absolutely new, filters are always suspect.

Fuel additives? The jury is out on this one. Some swear by them and some swear at them. For myself I abstain... And I own a lot of diesels other than my TDI's.

Bad injectors? Nozzles will wear over time. But at only 200k miles? I'd be inclined to take them to a shop that specializes in pumps and injectors and have them checked if you really believe them to be a problem. There's a good shop in Auburn, NY where we took both the pump and injectors for our ALH when we needed to be certain that they had a clean bill of health. I'm sure that you'll have a local shop that can do the same thing.

If I were to guess I'd be looking at either dirty filters or improperly set cam lash. Too little pressure will cause poor fuel dispersion at the injector nozzles. This, in turn, will cause a poor fuel burn. My reasoning being that it's logical to be suspicious of the area where recent work has been done.

Just try to remember that if there are no codes being thrown, then your problem is in an unmonitored portion of the system, or in a portion of the system where a sensor is supplying incorrect information.

One other thought... MAF and coolant sensors! Even though no code is being set these sensors sometimes go bad. This gives your ECU incorrect information and quite often causes performance and economy issues.

I replaced the MAF before the Malone Tune over a year ago. Yes this car had the cam wear known for this year when we bought the car( 2.5yrs ago). Frank Irving supplied the parts and Scott Krout(Jacksonville Fl) put them in. If I remember correctly it was a colt stage II with modified cam bearings & caps to provide better oil flow to the cam.Also this car has had the dual mass flywheel replaced right before we bought it. I will change the filters and will check into injector lash. Can I check this with my free version of the vagcom?

There has not been a huge drop in mpg. 38 has been seen when she drives it to work, but we went to University of Florida to see the son n law graduate driving all interstate at 68-70 mph and the norm would of been low 40's but it only got 38. Filled up before we left and then topped off when we returned. That's nothing to complain about since my truck gets only 15mpg but its lower than its normal. It could be a tank of crap gas affecting this also, who knows? I will change the filters this weekend!

And the low 40's has all been without the factory plastic cover under the motor(was gone when we bought it).

Before you do anything you need a base point to start from( this will also include deciding if it is worthwhile to replace injectors). You have indicated that one base point is 38 miles to the gallon. I want you to check for other symptoms. Check for black or white smoke or combination on start up( cold and warmed up). In neutral floor throttle from 1200 to 2500 rpm( partial warmed up and fully warmed up, note any difference in smoke if any). Now check for excessive smoke haze in side mirror by going through first to third at near or full throttle reving from 2000 to 3500 approx. in each gear ( fully warmed up only).

Does the engine run rough at idle. Does the motor shake unevenly at idle.

Try to come up with as many symptoms as possible as this will actually help with a proper course of action and show any improved results.

I had a similar problem with my '06 at 200k. My mpg's had fallen from 50 to 40. I had taken it to 5 different "experts" and none could figure it out. I had found that the actual boost pressure was considerably higher than the specified boost pressure at highway speeds. I took it to Scott Krout in Jacksonville, FL (4 hours away) and he was the one to finally figure out a problem with the EGR (no code). He also did a Malone Stage 1 tune. First tank after seeing Scott 52.5. I'd get it back to Scott.

Tom, what was the problem with the EGR in your case?
Hip, did you put new tires on recently? Has tire pressure decreased? Both will reduce MPGs. How about cam/crank timing? When was the timing belt replaced?