Spluttering 99' Golf 4 1.8 20v

I am experiencing spluttering in all gears, losing power uphill - didn't start last week(would only start in evenings) , had to replace 'speed/crank' sensor. Now starts fine, just jerks alot- no power on demand - need to stay under 100kph to drive around - mech.says to start with fuel filter and then possisible fuel pump - think it'd be the catalytic converter ??? Need to know asap!!!:frown:

Doesn't sound like a Catalytic or even an exhaust problem at all.

Perhaps a Throttle positioning sensor or even the coilpack

it was actually the Mass Airflow Meter that was causing the spluttering problem - had it changed up and been riding smooth for the past few months, As for not starting in hot weather: the crank sensor was the cause ! - thanks for the suggestions though !!!