Hi!
I have a problem with my bleoved 928 S4 ( I love the car, but of course less than my wife and daughter, to put things in perspective. BUT...)

I have not driven it much lately, about 2000 miles /year ( the car is a 87 S4 with 75000 miles)
and I noticed a severe loss of performance; I find it very hard to push it above 4000 RPM and reach speeds above 100, 110 MPH...
The engine does not stutter, I have had every possible filter changed,dito the spark plugs, added quarts of Techron, to no avail: I am getting passed by older Renault cars and delivery trucks ( in France where I took my toy from Miami Beach... Speak of a change).

Has anyone an idea of what can be wrong? I understand that it could be the coils, the exhaust system...

Thanks!

 

Bienvenue, mon frère de 928!

Could be a number of things, including a clogged catalytic converter, major vacuum leak(s), bad coil(s) and/or an inoperative 'flappy' control unit.

I'm sure as this thread evolves others here will be able to narrow down your root cause.

 

I had a similar problem today. After reconnecting the battery this morning i forgot to follow the procedure that let the injection brain recover his settings. The manual says that you have to start the engine and let it idle 10 minutes. I had the symptoms you described (total loss of power). So i simply disconnected and reconnected the battery again and followed the procedure. The car runs perfectly now.

Bonne route

 

Does this 10-minute rule apply to 87+ cars only, or are earlier models in there too??
Boy, this one sure may save a lot of people a BUNCH of money, time, and frustration..... :-(
Thanks,
Barry

 

I don't know for sure, but problably only for S4 and newer models. I learned this procedure from my user manual

 

Wouldn't hurt to do it anyway? What's a 10-minute idle if you're troubleshooting a money/time hogging car.

Andrew

 

There is something about that point in the <a href="http:////https://rennlist.com/techarticles/928/928batteryfaq.htm#electronic" target="_blank">FAQ</a>

Hope this helps.