You haven't spent much time with the ISI sims I gather.   All the
ISI/EA F1 sims have a pitlane speed limiter function hardcoded.  It
defaults to ON when you click the race button and enter the car.  
   The screen flashes the tach to SHOW you that the pit lane speed limiter
is activated.  So reading the manual and pressing the proper key will turn
that device off, until the next time you click race and enter the car when
it is parked in the pits.
   Now there is one interesting feature of the PrototypeC mod, the tracks
back then(1991-1993) did not have pit lane speed limits.  So the Mod makers  
raised the pitlane speed limits to 300mph(or kph) so that the auto pit lane
speed limit which engages when the pit assist option is enabled, would NOT
slow your car down to say 50mph while the AI all come screaming in at much
faster speeds. So in effect, for THIS mod, the pitlane speed limiter does
nothing..except flash the tach lights to indicate it's functioning.
    Your problem is one of possibly two subjects that are the SINGLe most
asked question for all the ISI sims & mods over the last 3 years.  Over and
Over again we have had to answer the same question, both here, and in the
various online forums available to the mods and users.  I will grant you
that the unique situation with the Group C mod may have been confusing, but
it's still amazing to me how many people (and I'm not singling you out)
rush to install a mod before EVERY becomming familiar with the core sim
product first.  I have very little interest in racing F1 cars, although I
do enjoy watching them, but I have spent a fair amount of time learning the
ins and outs of the F1 sims by ISI just so I'll get more out of the mods.
   So to answer your question:  Yes you will find this strange behaivor in
all the other cars in the group C mod AND you will find it(the flashing
tach) in all other mods and in the F1 sim itself.  But all you have to do
is turn off the pitlane speed limiter to stop it.  
I hope you enjoy the mod, they seem to have put a great deal of effort into
it.  I still don't know how the are able to introduce car changes midway
through a season.

dave henrie
 

Lumpy Cam ?

-Larry