Ever since I bought the car I've been having this issue that while driving, sometimes the power just completely cuts (as if i let go the gas suddenly) and after a few seconds it comes back. It usually happens about 3-4 times on a 20km run. And probably for the same reason, when the car idles, once in a while (about once per minute) the rpms get very low and it stutters to keep the car running but usually gets back ok. Check Engine light never comes on either.

I did the basic maintenance whe I got the car not too long ago (plugs, oil + oil filter, gas filter, air filter) and it made it better, but the prob is still there.

Perhaps something's wrong with the ECU or the coils ?

 

A couple things to try:

1 - disconnect the battery for a couple hous, then reconnect it. That's enough time to drain the caps in the ECU and put it into relearn mode. Once it's hooked up, turn the key to full power without cranking the engine. Let it sit until the throttle body/TPS is set up (you'll hear a humming at first - when that stops, it's set).

2 - three-part seafoam treatment (fuel, oil, and vacuum). Tons of info in the archives that Search will bring up.

3 - clean all electrical connectors underhood with electrical contact cleaner

4 - add a couple extra grounding points from the battery negative to various parts of the engine bay. Over time your chassis ground from the battery can corrode/degrade and cost you efficiency. I have a daisy-chained web going from the negative terminal to a bolt on the inner passenger side fender (it used to support the airbox), then to a bolt on the fuel rail, then to a stud on the ABS module, and from there back to the battery. This will allow your electrical system to conduct freely and well and your sensors should read more precisely.

5 - change the coolant temp sensor just because it's an unforgiving pain in the ***, it's cheap, it's easy to change, and it raises all kinds of hell on its way out.

 

I had a similar situation. Cleaning the MAF and the wire connections to it seemed to resolve it. Similar to what ITD suggested.

I would also check for vacuum air leaks.

 

hey devil... that coolant temp sensor... is there a DIY for the 12 v6 anywhere? mine is bad and i was told thats why i cant get it started sometimes in the morning and why the car bogs out at idle

 

phill coolent sensor is a breeze to install you pull a tab out and you swap no tools required

 

well if its such a breeze why cant i find it our find out how lol

 

http://lmgtfy.com/?q=audi+a4+coolant+temp+sensor

 

Pretty sure there's a DIY on audidiy.com or audiworld.com. Take off the throttle pipe and look down behind the passenger cylinder head. It's mounted vertically with a four-wire connector plugged in on top. Unplug it, pull the retaining clip off, and pull it out. Leave the coolant tank cap on so you don't get a huge volcano of coolant coming out when you pull it out. And make sure you order a new retaining clip - it's not included with the sensor and you're likely to break it (it's plastic and will be brittle from the heat).

 

see jeremy knws how to do it

 

can i get it from the dealership?