When i'm driving at low speeds 30-40mph i'll get a very small kick and i'll notice the rpm go up and drop, its not a high rev, i'll be driving around 1100-1200 rpms and it'll jumpt to about 15-1600 rpm and then drop. very random and only at low speeds once i reach 50-60+ it'll never happen again.

at first I found a hole in a breather hose, i had it replaced and was told it was the only one with a hole. my only other guess would be to replace both ECT sensors, my CEL isnt on, but i got it checked and it does pull the code saying my engine is too hot, coolant sensor.

i guess i could pay the $150 diagnotics fee, but i'm tempted to replace the ect sensors. I know the A8 has 2 of them.

thoughts?
thanks in advance

 

The "kick" you describe sounds more like the torque converter clutch kicking in and out...not an engine problem. Usually NOT a bad torque converter (or TC clutch), but the valve that controls it. Might be worth checking the atf level (correctly...very precise procedure), and possibly even adding "Lubeguard Red" to atf, if you don't find a problem elsewhere..it often frees up sticky trans valves:

LUBEGARD ATF PROTECTANT RED FOR USE IN ALL AUTOMATICS | eBay

The ECT sensors (1 sends signal to ECM, the other sends temp gauge signal) do NOT control coolant temp in any way...they just read it and the ECM uses it's sensor to help adjust tune (fuel mix, etc...) to engine temp.