Technical Idle

[sxchris]

So I changed the thermostat on my 95 899, now it won't idle, will only keep running with my foot on the gas.
Took it round the block, and drives OK, but soon as my foot comes off the gas it just dies.
Have checked all connections to everything and they are all fine.
Please help a fellow cinquecento owner out ?

 

[SpreadLegsNotLies]

Why change the thermostat? Did it overheat?

Could be a few issues, vaccuum leak (can upset idle), idle control valve (could have failed closed), not sure how much the temp sensor plays in idle control but that could be dodgy and giving a wrong reading? If you hold the throttle slightly open does the engine miss/ stutter just above idle or is it running clean? But given you have been messing with the water system it could be the head gasket if the car has been overheating? Tried running it without a thermostat in the housing?

Obviously can't be 100% without a pressure test but other symptoms are loosing water, water bottle bubbling after switching off the engine, white gunk in the water bottle, on the dip stick or oil filler cap, steam out the exhaust. On throttle you're stopping water entering the cylinders and then on idle it's letting some get in there and killing more than one cylinder?