[A4] Engine cut-out, spikey idle and other weirdness...

[Phil Yee]

 Tyson, It may be the MAF, but I would think the ignition coils might be it.  When my MAF went bad, it caused pinging more than what you described.  I've had 2 coils go out on separate occassions, with similiar conditions . . . any type of acceleration will make it skip and lose power.  i assume your check engine light goes on when the trouble occurs, and stops when the problem goes away?  Go to your local Kragen/Pepboys/etc, and buy a $70 code reader (worth it's weight in gold), it'll tell you if it's a misfire (coil) or MAF, and it'll tell you which cylinder.  you can then order the right coil online for $35 each.  look up recalls, that year may be eligible for a factory replacement of coils - there were a few bad  years. your car is not drive by wire, that started in 2000 onwards.Good luck.-Phil--- On Tue 03/20, < a4-request at audifans.com > wrote:----------------------------------------------------------------------Message: 1Date: Mon, 19 Mar 2007 16:28:11 -0700From: 
"Tyson Varosyan" Subject: [A4] Engine cut-out, spikey idle and other weirdness...To: Message-ID: <009701c76a7e$429eb7b0$6e11030a at enpower>Content-Type: text/plain; charset="us-ascii"Hi Guys,I bought my 98 A4Q 2.8 30V about a month ago. Today was the first time thatI took the plastic covers off the engine bay and this is why: Driving back from my dad's house the car just suddenly started acting out.Cruising along at 3000 RPM the engine would just cut out. The dash lightsdidn't light up or anything (as they would in an electrical power loss), allelectrical gizmos continued working, etc. It did not feel like losing asingle cylinder - it felt more like hitting the rev limiter - just totalignition cut that jerked the car pretty noticeably. It would only last forabout a second and then everything would be OK again. It did this a fewtimes until I pulled over at a gas station and popped the hood. Idling there for some time the idle suddenly started jumping around - jumpedto 
about 1500 on its own, then almost died, then jumped again. Then theengine just cut out and died altogether. I popped off the covers, reseatedthe plugs around the intake - a 3-pin, which I assume is the TPS and another2-pin, which looked like an idle controller. Then started the car back up and drove on. The problems continued to happenabout once a minute or so, mostly under cruise and light acceleration. Itdied again at a light. Then after some time (maybe 10 minutes) the problemswent away completely.I have noticed that a dirty MAS seems to be a common problem on these carsand this sounds totally like something that a MAS would cause. If there isanother sensor in the system that can make the ECU cut all ignition, thatmight be it too. It feels like a deliberate ignition cut by the ECU, but Iam not sure why...#1 Where is the MAS?#2 What should I use to clean it?#3 Just for curiosity - is this car drive-by-wire (where the ECU opens andcloses the throttle plate based on a sensor 
attached to the gas pedal) ordoes it still have a physical cable connecting the gas pedal to the throttleplate?Any other ideas, suggestions are welcome. Tyson VarosyanTechnical Manager, Uptime Technical Solutions LLC.tyson at up-times.com