Those of you who have read my previous posts regarding my surging problem, and are interested, continue reading – for those of you who don’t care or who do NOT have the 1.8T, please hit your browser’s back button.

But before I go on, I couldn’t help but to think back to all those posts I’ve read where various posters have said something along the lines of: “I use this brand X 92 octane and brand Y 92 octane and brand Z 92 octane is total crap”. I’ve always asked myself the question, how the heck would one brands superiority over another manifest itself? I think I know, it’s how SMOOTH the engine feels and not necessarily the feeling of power gained over one brand versus another. This is the first car I’ve owned that the Brand and not the grade of gas make a big difference (the grade defaults to 92 or better octane). I believe this is due to the design of the engine management system (namely Bosch) and I think Audi should be a little more demanding of it contractors/vendors. This engine is running on, or over, the edge of stability at certain operating conditions.

Anyway, the below is what transformed my driving experience for the better.

Problem History:
The car surges when driving in suburban stop and go traffic in 4th and 5th gears, while accelerating to keep up with the flow of traffic. The car does this whether the engine is cold or at normal operating temperature.

Solution: Change Transmission Control Module

My Impressions: (between TCMs 8D0 927 156BM and 8D0 927 156CL)
1) Transmission shift points have moved up 100 rpm in suburban traffic (this I like)
2) Downshift seems to occur with less throttle application (this I like)
3) Transmission Torque Converter now locks up at around 50 mph instead of 22 mph (this helps to mask-out the engine surging problem from 1600 to 2500 rpm)
4) The Intelligent Hill Shifting Program for climbing hills is no longer active (I have mixed feelings about this)
5) The engine still surges, but now, only felt at medium to heavy throttle application. With the Torque Converter unlocked below 50 mph and with light throttle application, the surging is barely detectable (this is an improvement)

In Conclusion:
Installation of the new TCM has diminished the drivability problem in suburban traffic to an acceptable level. So, Francis M. (Audi District Service Manger) and the A-B service technician deserve “a job well done”!

Vic
99.5 1.8T tip

When I first got the car I complained several times about what I perceived as "slipping" in 2nd gear between 2000-3000 RPM. Come to think of it, I was going exactly 22 MPH when this happened.

I wonder if this could qualify as a warranty claim? The dealer [correctly] said this was normal (it was at the time).

I don't want to ask anything unreasonable, but if there were a way to get the improvements under warranty, I'd really like to pursue that.

I guess the best thing to do would be to just call AoA. I'll report back if I have anything useful.

Paul
'98.5 A4 1.8TQTSS

Anyway, below is the a breif summary:

Condition: Customer report one of more of the following conditions:

1) With trans in 5th and light throttle, with < 1400 rpm, engine surges.

2) When coming to a stop and as brakes are released, the transmissin will shift from 3rd to 2nd the transmission will shudder (similar to brake rotor shudder)

3)Vehicle lacks power due to trany upshifting too fast.

4) After climbing a hill, trany upshift is delayed.

Service: If any or all of these conditions exist: replace TCM with part # 8D0 927 156CL.

This TB is dated March 8, 1999

the both exhibited the same surging as mine, under the same conditions.

Maybe I'm too sensitive to this problem, I've done all the tune-ups on all of my cars in the 60s, 70s, and 80s. My 1.8T tip felt like it was way past time for a tune-up. But, someone who hasn't done their own tune-ups might not even notice the surging and just think their feeling bumps in the road. My wife doesn't feel it at all, go figure.

Vic
99.5 1.8T tip 8Kmiles, bone stock