My 1992 Audi 100 has a rough idle,popping noise in the exhaust and is shifting rough

Car starts first thing in morning after driving and turning the car off when I try to start the car it will not start. I can hear the starter moter spinning, but it will not engage. Is this a starter or solonid problem.

how to replace thermostat on audi 1994 100s

The response to my question on the electrical assembly indicated that I might have to remove the key cylinder. Just how do I remove that part? I don't see any access to that part.

The electrical assembly on the back of the key switch is bad. In order to replace it, I have removed the lower panel, the steering wheel & steering column switch assembly, and the instrument panel assembly. The electrical assembly is secured to the back of the switch by two small screws. There is a aluminum crash bar surrounding the key switch. How do I access the retaining screws? There are no holes in which to put a screwdriver.

the brakes are going all the way to the floor!I replaced the master cyclinder still the same so i tried to bleed the brakes nothing what my p and how could i pin point the problem

There is no "juice" going to sparks plugs. I changed the coil and still nothing. What could be the cause of this?

Where is the location of the plug for the code scanner? Where is the crankshaft sensor located?

Can the coil springs be put in upside down??

The headlights and sun roof work sometimes and then they don't and then they do again and not at the same time,the lights work,sunroof doesn't and vise versa.The drivers side seat heater worked and then stopped working,the fuse is OK

How do I by pass the programmed key to start the car? The key I have to it has been broken.