1.6 petrol. car will start with full throttle,wont stay running unless you keep blipping the throttle to keep the revs up above 2k.when engine cuts out there is a lot of induction roar and a load of smoke out the back.i have replaced the fuel filter. could this be the cat restricting the exhaust gases?

 

Sounds like an air leak. Pull the servo pipe off the servo and put your thumb over the end, keep someone in the car keeping it idling as low as it can you should feel vacuum (a strong vacuum)

 

thanks for the advice,i have pulled pipe off the servo like you said and there was plenty of vacuum,so i turned off engine and i checked all other hoses and made sure they were tight and not blocked,cleaned up the air flow meter connection which wasn't dirty really but did it none the less turned the key and it started as normal,though it does have a really eggy smell which i am guessing could be the cat?

 

Eggy smell could well be the cat, if you get underneath the car and give it a bang, does it rattle?

 

gave it a bang and a shake and doesn't seem to be any rattling,have taken it for a drive also and the smell seems to have gone? thanks for your help guys.

 

Sounds to me like the opposite, I.E its running to rich, hence you have to keep the throttle open to compensate for extra air needed, the smoke is also a good indication of this, you could check the CHT sensor as that may have gone and telling the ECU it's colder than what it is, hence it's fueling for what it thinks is a very cold condition.

Martin