I have a 2000 Punto HGT 1.8L. I have been driving myself crazy trying to figure out a very sporadic stalling problem. My car will stall out whenever I am approaching an intersection or roundabout and I begin to decelerate and either press in the clutch and hit the brakes to downshift or kick it into neutral.

The stalling is VERY intermittent. Somedays it won't stall at all. Other days it seems like it stalls every time I come to a stop. If I am sitting in the driveway and rev the engine. 8/10 times it returns to a perfect idle. Sometimes it will dip too low and stall out.

Some things I have done so far

-changed engine coolant temp sensor
-changed spark plugs
-disassembled and cleaned the entire throttle body to include the IACV and MAF sensor.
-checked for vacuum leaks.

The car starts great and runs great. I just can't figure out why it is stalling some days and not others.
***I did have the battery changed about a month ago and I believe this is when the problem started. So I'm guessing it might be electrical at this point?

hey foltzie, you every find a solution to this? I have an 05 HGT with a similar problem by the sounds of it.

https://www.fiatforum.com/punto-ii/457133-punto-hgt-revs-dip-when-dropping-gears.html

The throttle position sensor can cause this either it's closing the body completely starving the engine of air or not sending the correct signal to the ECU so the injectors flood the engine.

Take the plug off and inspect the terminals. Give them a good clean and squirt of contact cleaner or WD40 and see if that solves it.

The MaF sensor can also cause this if there is power loss before cutting out. Same as above but take the MaF off and make sure there is no crap build up in there.