Does anyone knows what "Slow Down 1/4" means?

IIRC, it means that the sensors on the exhaust before and after the cats are sensing either a very lean or rich condition. If the car is running to rich on that bank, and if it is dumping unburned fuel into the exhaust, it can cause the cats to overheat and do serious damage. It's possible it's a bad sensor, but you should get it checked out as you could be doing damage to you cats.

And yes, the system is set up to shut down the bank that is throwing the code.

 

http://www.the348.com/technical/repairMaintenance/slowDownLights.html

 

It means "you should have read the owner's manual"
(https://owners.ferrari.com/)

 

1/4 is the cylinder bank with 1 to 4
Slow down means a fire danger exists and suggests you limp to your garage as slow as possible.

Unlike the common 'check engine' light this condition can be serious and demands immediate attention.

The 'slow' lights are turned on by exessive exhaust temperature indicated by a sensor in the catalytic converter. Fuel isn't burning in the cylinder but pouring into the exhaust manifold and igniting. Common problem is ignition malfunction.

Senior moment prevents me from remembering whether 1-4 is front bank or rear bank. So I will leave the front/back bank issue for others.

Aside - I'm embarrased for those who, when asked a simple question, feel impelled to give smart alec non-answers and I apologize for them. That attitude not representive of Ferrari owners.

 

The 348's engine is mounted lengthwise, so it's a left/right question, not a front/back one.

I didn't find which was which on a quick google search, but that would be in the owner's manual. (Available at the link listed in the "non-answer" response above.)

For a quicker overview, there's the Owner's Primer page: http://webpages.charter.net/aircover/348/1994Ferrari348Spider.html (caution: large page). (It describes the "slow down" lights at length, along with a lot of other info, but which bank is which isn't mentioned there, either.)

But a Ferrari is such a mechanically elegant machine that if you just jump in and drive it like a road appliance, you're missing out big time.

When I bought my first new Italian (an Alfa) several decades ago, the dealer (race shop) walked me through the instrument cluster, the engine bay, and took me out on a "check ride" drive.

Reading the owner's manual from cover to cover should be the first thing you do when buying a performance car. You don't want to be hunting for the light switch or wondering "what's this knob do?" to distract you from driving.

"Drive" is a verb, not a gear.

Certainly, I'd expect that you'd want to read the manual before going online with basic questions -- unless you didn't get a manual with the car (used) ... which is why I included the link to the owner's site where you can get one.

(Besides; I learned while mentoring young engineers that if you just give them the answers, they never learn how to find out for themselves. And what you get from a Ferrari manual will be more reliable than the Internet. Some of the data here is good. And there's some real garbage on the 'net, too.)
(And if "brevity is the soul of wit", it bothers me that it takes such lengthy explainations to ignite comprehension on the web, these days.)

 

Looking in the engine bay from the back of the car the 1/4 bank is on the right. You can also look on the cam covers and see the numbers marked just under the spark plug holes. In addition, the 5/8 bank as the firing order marked on it.

I know your new here so.........next time use the search button first, that way the boys don't bust your balls about a question. For example I was tempted to say you were driving too fast.