2011 JSW TDI - First Drive Off the Lot...

Just purchased this car at DeMontrond VW in Houston on Saturday. It's a Toffee Brown Metallic color w/ a tan stripe across each side. The previous owner took immaculate care of the car as evidenced by it only having 26K miles and no damage at all. Even the paint was perfect.

I only paid $12,100 OTD and this dealership has a transferable powertrain lifetime warranty on the car. Not bad.

Next, I drove straight to Cedar Park, TX to have the car tinted. I chose Rayno S9 for those of you who know tinting. I loved it on my 2015 Passat, so gave them repeat business.

The noticeable difference between this 2011 JSW TDI with the "fix" and my 2009 JSW TDI (Dirty Diesel) is that I lost about 5 MPG even when I was gentle on the accelerator throughout the trip averaging about 70MPH. I was at 36 MPG. On my 2009 JSW TDI, I easily get 40 MPG no matter what.
Power feels the same, but overall it almost seems like the engine is holding back some from whatever the "fix" does to the engine.
I know this is the consensus among TDI folks.

The question now is whether to respect the warranty on the emissions or take it to a tech to get it recoded.

Anyone in this situation, I'd appreciate some opinions or experiences.

Your choice. People are very happy with their tunes. But don't expect the warranty to cover you. It might and might not. The mantra is if the warranty means anything to you leave the car alone. If you don't care and are willing to assume all responsibility if needed, tune away to your hearts content. Tunes can provide more performance but none of them promises any mpg gain that I have read. Some drivers have claimed increases though, but different conditions and driving techniques can produce those as well.

Lightflyer1 said:

Your choice. People are very happy with their tunes. But don't expect the warranty to cover you. It might and might not. The mantra is if the warranty means anything to you leave the car alone. If you don't care and are willing to assume all responsibility if needed, tune away to your hearts content. Tunes can provide more performance but none of them promises any mpg gain that I have read. Some drivers have claimed increases though, but different conditions and driving techniques can produce those as well.

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Thanks for the advice.

For now, I'll leave it alone. I suppose 35 MPG isn't bad, even if it isn't as efficient as I'm used to.

The sensation that engine is holding back is likely from retarded timing. Retarding timing in a diesel decreases NOx but increases soot. I hated that feeling so much after the fix I did a Malone stage 1 on my JSW and it helped a great deal. The mpg’s never achieved pre-fix levels but they did improve a bit, likely because the engine produced more power and labored less.