Technical only reving to four thousand and then popping!??

[jbpepsi]

I have a 1997 fiat coupe 2 litre, 20v, turbo, 220bhp. When I start the car and keep my foot on the accelerator it will only go to four thousand revs after a while. Then when it does it will start popping! I have just replaced coil packs and airflow meter. I checked all air pipes, relays and fuses, It has a new timing belt and no luck. Also at times the relays at the front of the ECU click.. Please help I have tried everythig and its driving me mad!! Any help would be appreciated

 

[davea20vt]

is the car chipped ?

 

[unoturbo1]

my uno turbo does that. its overboosting or the overswitch is playing up which leads to ecu