2001 Passat, sometimes its hard to start. Now

abs sensor is dirty or bad. try unhooking the abs sensor located on back side of wheel hub......

Transmission problem. I suggest getting it serviced or put a new transmission in it

On the 2001 Volkswagen Passat, there is one reverse tail light (bulb) per side for a total of two reverse tail lights. The following link shows the inside of the 2001 Volkswagen Passat tail light.
Link to 2001 Volkswagen Passat Image

transmission might have a leak.If there is there is probably not enough fluid in the transmission.Do not drive it or attempt to drive it.

sounds like transmission speed sensor is broke and not telling tranny to shift test it with voltmeter

Sometimes sensors can just be dirty, try wiping them with a clean soft rag.

There is a vacuum line that runs under the manifold, it seems to be a very common problem.

Go to autozone, have it scanned with a OBD2 scanner and come back and post the trouble codes, also have the autozone guys look for a bad vacuum hose that comes off of the manifold, they might find it right away.

it can be your starter or the silencer. U have to get it checked or it can be your ignition. I'm pretty sure its 1 of these 3 things. I dont think its silencer buh it can be ingition or silencer.

sounds like a vaccume leak at brake booster or if peddle is hard replace booster

throttle body is located at intake manifold ..follow snorkle from air cleaner to where it attaches to motor ..looses hose and clean with carb cleaner there..open blades(throttle) to get behind entry good also..... fuel filter is located in tank and in line from fuel tank just in front of tank inline with fuel line...good luck