My 98 Deville stalls every once in a while while moving. The ODBII code is # 1599. Which
says "vehicle stalled or nearly stalled" I have to restart the car when moving or pull to the side and restart then. This always occurs in deceleration or at lower traffic speeds. Help!

 

engines run on three things, fuel air and spark. if its stalling its not getting one or more of these
if its not getting any codes its probably fuel, check/replace the fuel filter.
caddys have a lot of electronics that control how much fuel air and spark go into the engine, they should pop a code up when they fail.
good luck

 

My 96 deville did the same thing and if you can believe it; it was still under warranty and the dealer did nothing to fix it......... It sounds like your problem is the same as mine. It is the fuel pressure regulator. A small vacuum operated device that costs about 50 bucks and is very easy to replace yourself if you are mechanically inclined. Buy the part, remove the large plastic cover on top of the engine and look for your existing one and replace it. I was intimidated at first; but it only took me ten minutes. The car ran fine immediately, good luck.

 

hmm...this is strictly an intermittent problem?

 

I had stalling problems during idle.
This forum has a tech tip about checking the regulator to see if it leaks.
I forget the test, but my regulator was leaking. Car had about 70K.
I replaced it, and idles like a new car.

Look on this site. It's here.