I have a 2006 volkswagen passat 3.6 litre v6- have had this car about a year now, 60,000 miles, no problems until recently. Last week I started noticing that when I am driving, with my foot on the gas, it would intermittently act as if it was decelerating at a rapid pace( will drop gears, is NOT a coast)- even when I floored it!! As soon as it stops responding to the throttle I can floor it, nothing will happen, then let the gas peddle go- then reapply gas and it will act perfectly normal- no flooding, no nothing!! I have been able to keep it floored( while it is decelerating) for about 30 seconds, and it seems to make no difference. The only other problem that I have recently noticed was that my cruise control was acting only intermittently as well. Oh, also while all this is happening it isn’t throwing any check engine, or error lights. I have taken it to the dealer, and also to another specialty mechanic( with master certified technicians) and neither seem to find any problem with the vehicle, the only code that they said was found was one to the mass air flow??, but they weren 't sure that was actually the problem, as, of course, they cannot seem to replicate my problem, even though it is now happening quite a lot. HELP!! I am worried about driving my car now as it is quite a hazard when it decelerates rapidly, and to top it all off, we were supposed to leave on my honeymoon for a 2,000 mile road trip in 10 days. Go figure right?! Ok, so if you have any suggestions, or have ever heard of this problem, please help me!
Thank you so much,
Christina
Today’s cars have become so complex electronically, problems like this can be very difficult if not impossible to fix…If you can cure it by manipulating the throttle, the first place to start might be the throttle position sensor, a not too expensive part…
A fun rental car comes to mind. How many real honeymoons are there in life? A 2k trip in a nice car may be worth the 50$ a day rental. Maybe less. Then the mechanics can puzzle the car without you wanting it back for stupid reasons like going to work or getting food.
Maybe the computer can be reflashed like other makes, maybe not. Some problems have been fixed this way.
thanks for the comments guys, will look into a rental car, might be the perfect solution for the trip- I do hope they can figure out the problem, will definately ask them about the throttle position sensor, and reflashing. will let you know if they give me an answer 
Just be happy. Its worth it. Peace and good luck.
the car has drive by wire for the acc. pedal. maybe the pedal is getting dirt on the circuit board???
@Big Marc: It’s likely the board for this is located elsewhere and operated by a cable from the accelerator. On my 2006 Chrysler, the electronic throttle is actually in the trunk. That said, it is quite possible that the electronic throttle is going bad.