My fiat idles but wont rev

have you checked the fuel filter??

Could be either or both: the "throttle position sensor" or the "idle air control valve". But could be something really simple like sticking throttle cable or an inlet air leak. But am willing to bet it is one or both the TPS or IACV.

I would think that the appropriate thing to do would be to ask the person/business that renewed the engine.

Have you had the engine control computer scanned for fault codes? Do that first.

Is the engine idle just set a bit low anyway? Can you access the idle adjustment and turn it up a tad? The sluggish drive may be in need of an engine service but a 1.3 is small for this car. Check out online car owner forums to see if others think so to.

recheck your timing marks and or vacum lines

First scan for a code,then you will know whats wrong,need OBDII scan tool.

hi patricia
FIAT engine light flashing means the ECU needs adaptation,
you can do it yourself just follow this procedure.
( remember not to accelerate unles is stated) start the engine
let it to warm and wait for the cooling fan to come ON then OFF 3 times, like ON,OFF,ON,OFF,ON,OFF. After the fan cuts off the third time accelerate fully down let the engine rev up to 4000 only then leave the accelerator let the engine goes down back to idle, do this 3 times.the engine light should go away.
good luck

take your cylinder head out and take it to the engineering and ask them to change your valve sterm seals then your problem will be solved

Does this have a self diagnosing emission system, like the USA markets OBD 2 system? we don't have Fiat's here since early 80's, this sounds like a Throttle position sensor issue or idle speed control valve problem, if there are trouble codes stored in the control module's memory please provide them to me along with the definitions, but check the TPS and Idle speed control first.