How do take Audi Ignition switch out? It is an a6 Wagon Quadro 2.8 engine

2.8L USA car? not told country
look here yet?
https://eautorepair.net/Marketing/Default.asp

engine pressure not transmission;.
the cluster lamp lies to you. that? some cars have 2, on for lamp and other for VVT !
it is switch and most cars it turns on below 7psi.
lamp K3 and switch F1 is its name. (German spec names)
older engine its on top front (facing engine) cam shaft cover)
some Audi dealers show the parts list with all parts show graphically
best is try there first, then buy the service manual and find it.
name (yes OEM audi sites some do not show it)
Engine Oil Pressure Switch. OIL PRESSURE SENDING UNIT. OIL TEMPERATURE SENDING UNIT. Part Number: #06A919081J ask here on real forums Audi

some have 2, a switch and sensor oil pressure.
1 just behind the oil filter mount.
and one near cam (top right bank facing bank)

https://www.audiworld.com/forums/a6-s6-c5-platform-discussion-7/oil-temperature-sensor-location-99-2-8l-2763857/

post there, is best. pure AUDI there.

Take out the 30th fuse from SB42, in the instrument panel fuse box for 30 seconds and then reinstall. This will reset the control module.

I’m happy to assist further over the phone at https://www.6ya.com/expert/kim_3202917d7c587455

Vaccum leak or fuel or air filter

That fuse is integrated into the brake light system. the switch is located under the dash attached to the brake pedal.

For 2007 Audi A6 depending on the engine type, there are two placements for cabin air filters:
1. The cabin air filters are placed on the right bottom side of the central console - passenger side, for 2007 Audi A6 Avant. Remove the carpet and behind the plastic cover are cabin filters. When installing new filters see for the correct position - air flow is indicated by an arrow. See pictures below:

2. For the second placement, besides you need to remove the glove box for access and replace cabin air filters.
Check first your car situation. If you will give me your e-mail address, I will send you photos with cabin filters replacement for 2007 Audi A6, because the www.fixya.com website is limited to 150 kb traffic.

most likely it is only an ignition coil thats bad causing one of your cylinders to misfire.

That indicates you need to enter the radio reset code which came with the car. Or see you dealer.

ALL 1999 Audi A6:
A6 Quattro Sedan
A6 Quattro Wagon
A6 Sedan
have the 2.8L DOHC V6

Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!

underneath the car in the engine area up in front just back past the front bumper you will find an aluminum cross hatched (criss cross lines) oil pan at the lowest point is the drain plug.

Starter switch. Plastic and cheap, my 98 A6 did the same thing... I replaced thousands in parts, turned out to be a cracked ignition switch which is a very common Audi problem!