obLu

2007 Q7 4.2 34k miles. Off and on we've had an issue where sometimes you put in reverse and it kind of chugs rocking the car back and forth as you're pressing on the gas to back up. Today though, on the freeway going about 70mph (in a 70 zone) I started to switch lanes and accelerate to pass a slower car. Instead of the transmission kicking down a gear it made a couple of loud bangs accompanied by the car jerking ... kind of like it was going into neutral and then banging back into gear? Did it about 3 times, then carried on as if nothing was wrong.

Transmission seems a little funny now, like it's not working the same, but that could just be my imagination.

Going to be at the dealer for a seat replacement and 35k service here this week, but was wondering if anybody had experienced anything like it. If the tranny is going I want to push hard for a replacement before the warranty expires. But I'm almost wondering if this was mis-firing from a failing coil pack?

Audivergin

Hi, I have had a 4.2L Q7 from new and at about 30k I also started to feel some sort of surge or instability when I put the car in reverse. I starte to log temp and whether conditions to determine if heat, cold, humidity or anything else could be causing this. My dealer had the car in twice. They claime it was due to carbon build up in the manifold and cleaned it first time. It improved some but the issue was still there. At the second attempt they had to remove my air intake manifold (or so the dealer rep told me). The problem was fixed as the car was under warranty but I am an engine guy and I don't believe the carbon build up story. I think they have another issue, which they are not being honest about. Any way I now have nearly 50k miles on my car and everything is fine.

Jusforfun

1st step hook it up and check fault codes. Audivergin if you dont mind I would like to add your mech fail report to spreadsheet.
What MY is your Q.
When did car arrive or approx when was repair carried out.

Audivergin

Justforfun,
sorry I didn't get back to you sooner. My Q7 is one of the first available in US. I picked it up Sep 2006 (MY 2007). The problem started around 30k miles. The final repair was around May/Jun 2009.

Hope this helps.