Symptom: Excess smoke, engine will not rev past 3,800rpm
Cause: Faulty or disconnected MAF sensor.

Symptom: Poor low rev performance
Cause: Out of spec MAF sensor

Symptom: Excess smoke, poor performance, possible hissing noise
Cause: Split intercooler hose

Symptom: Engine starts fine but does not respond to the throttle for many seconds.
Cause: Badly out of spec MAF sensor

Symptom: Sudden engine failure – engine just stops for no apparent reason
Cause: Possible pump failure – eliminate other possibilities first £££

Symptom: Poor performance after driving in wet weather
Cause: Soaked air filter and/or MAF sensor. Clean sensor carefully with alcohol or similar to avoid permenant problems. Check that air intake hose is not displaced which can allow water to be sucked up - WARNING if the engine ingests a lot of water then it may destroy it.