Warning: I'm a noob of this forum, and with cars in general, I hope I posted this in the right spot, and my ignorance doesnt offend anyone.

I have a 2005 Audi A4 1.8T

A few things have happened recently which are clouding my assessment of what is wrong with my car.
1.) I changed my own oil for the first time ever (this is the first car I have owned for myself)
2.) The weather is getting cold.
3.) my car went in to the shop for a bad transmission control module (was replaced) and a bad coil pack (was replaced)

All of these things happened around the same time so its hard to say when exactly the vibrations started relative to all of these things. I can say that it did not occur before all of these things and its happening now.

The vibration occurs especially when:
1.) I put the car in reverse it vibrates very loudly for 1-2 seconds then gets quieter until its a modest vibration.
2.) when i slow to a stop it vibrates significantly for 1-2 seconds then stops vibrating.

Its as if the engines RPM is getting too low and then it almost stalls out until it recovers. The tachometer is consistent with this guess. it hits about 800RPM when it starts vibrating, and then rises back up slightly above 800 and stops vibrating.

I took it to the dealer and they said they didn't notice vibrations.. I feel like if I went back there knowing what the problem probably was they would take me more seriously.

Any ideas, advice, anyone has would be greatly appreciated. Please ask more questions or give me tests to perform if I have not supplied enough information.

 

Hit the econ button on HVAC or make sure all HVAC is turned off, vibration still there?

Maybe more than one bad coil pack?

 

Mine was doing something similar, then once in a while it would hesitate a bit while accelerating (which made me think I had a transmission issue)

Soon thereafter, my engine shuttered really roughly , threw a check engine light, then promptly fixed itself again. I check the codes, and replaced a coilpack.

All set now.

 

The HVAC button seems to have no effect unfortunately. Vibrations occur with our without HVAC on when its cold and first starting. And they dont occur as much with or without HVAC after the car has warmed up.

I feel like something is resisting the engine. When Im accelerating uphill the acceleration comes in waves.. the car pushes and then slows and pushes again in waves (its very subtle).

If i accelerate from a stop the car bursts then slows then bursts again before coming to a steady rate of acceleration.

If i release my foot from the acceleration and coast, the car feels like its rolling but then it slows down fairly rapidly as if I down shifted or something. and goes back to rolling and then vibrates before a complete stop.

I feel like something is resisting the engines normal behavior.

Any more ideas? Anything I can test?