Had to take my track down as we had visitors. When I put it back up I did a different layout and so the story begins.
I had SSDC v 5.4.2 and firmware v 1.09. I tried to re-record pace car data for the new track layout. After clearing the old data I could not record any new data. Tried numerous times with different cars, ID's and controllers, you name it. Read some more threads and went back to SSDC v 5.4.1 firmware v 1.07. I recorded pace car data successfully at this point but could not get the cars to run consistently. I did have to check and uncheck the boxes a number of times for dynamic and progressive braking and pace driver and variable throttle to get them to run at all.
The next issue was that one of the pace cars would do 4 or 5 laps then slow down to a crawl. After passing the track sensor for the end of the lap it would then go ballistic and deslot within a couple of seconds. This was not consistent to one car, it did it for both at different times.
I am now back to SSDC v 5.4.2 and firmware v 1.09 using the pace car data I recorded in SSDC v 5.4.1 with firmware v 1.07. I am not game to try re-recording the data. At first only one car ran, did 4 laps, slowed for a lap then went crazy. I concentrated on this car only and unchecked and re-checked all the flags in the driver window a number of times. Ran it in a race on it's own then ran it in free practice mode. It nows seems to run OK with variable throttle consistently.
Did the same with the second car, Check and un-check the flags in the driver window repeatedly. Ran it in a race on it's own. Then ran it in free practice.
Both cars ran OK with variable throttle with just the two pace cars on the track. Don't know what will happen when I next go to use the track (it's all powered down now).
The upshot is, the pace cars are really twitchy no matter what version of software/firmware I use. I can get them to settle down by repeatedly checking and un-checking boxes and running them in both race and free practice modes.
It seems that something is not registering properly within the software unless boxes are repeatedly checked and different modes are used to run the pace cars. After doing all this they seen to settle down.