I bought a 94 S4 last year and have been working out some of the issues, for the most part she is solid and drives well. The nearest Lotus dealership is over 200km from here and they are not equipped for obd1 so they cannot assist much with driveability issues.
I bought the usb-obd1 aldl cable and have run freescan a few times, the issues are not consistent but I have a few suspicions and was hoping for some insight from the more experienced owners.
The first issue is that the idle has always been very erratic, some days it's 950, 1400, 1700, 1150, etc. Lately when I first start her after sitting even just overnight she's very rough and stalls unless power is added, after she reaches temp she runs fine. Also when I first add throttle she drops rpms and can stall unless I add more throttle so I always need to start with lots of throttle.
The second issue happened just a few times, if I am accelerating to highway speeds I can be in 3rd, 4th, 5th gear, 3.5k-6k rpm I just lose all power. As I come of the throttle a little and back in it comes back.. the more I tried to replicate this it seems that I need to have the throttle to the floor for a couple of seconds for this to happen.
I am also showing a few codes...I think they may be related to this issue and may be corrected once the situation is resolved.
Based on these scenarios I am thinking that I am having issues with fuel/air mix and it could be related to the TPS and IAC, I am attaching 2 logs, one shows the idle from start, the other shows the power drop off at highway speed
Thank You in advance!