1985 Deville stall problem

I ran this issue about 2 months ago. We have tried everything we know and it still stalls. I have read some other posts and it seems like there are other years with the same problem. Stalls when slowing down or braking. I have not seen a response that has helped solve this issues yet. Someone has to have run across this and solved it or we would have lots of caddy's stalling. Please help!!

We have tried the fuel system, computer, distributor, ignition control module, and I probably forgot something. Help!!!! Even my mechanic has given up.

qamike2001

if there is a vacuum leak, this could cause an idle stumble or engine cut-out. this is just ONE of many options, but if this ONLY occurs while braking, or even idling, while off-load, it sounds to be vacuum related.
does it occur ALWAYS? or only after it has ran and warmed up?
spraying lightly, a can of starting fluid into the engine bay, while idling, in different areas, may cause an idle increase;
if it does, this is the area of a potential leak.
has the filters been serviced, and a tune-up done?
if yes, then move through other components (as I have seen you have done so, from the post).
is the idle set too low? for an auto with V8, should be 750-1000RPM, but this is at sea level; same with timing, whatever the book says, is at ZERO feet elevation. bump the idle up a bit, and see if it still falters.

if so, I'd say something is robbing the power, or choking the engine.
has the catalytic converter been changed? or the EGR cleaned and serviced?

hope this helps,
chris
nrt racing