Hi all,I'm having a complete nightmare of a time diagnosing a fault on my parents 1400 LX (petrol). I brought this car for them as a run around as their previous Xsara was written off when a council truck backed into it at speed! Their previous model was a 1.9D on a 98 R reg,and I might add that it was the most reliable and rott free car they have ever owned! Hence why we went down the Xsara route again although this time being a 1400 petrol and the phase 2 model. Anyway,after about 2 weeks of ownership the timing belt snapped so I sourced a new engine with only 55k on it for £120,changed the timing belt and tensioner,water pump,oil and air filter and spark plugs before putting the engine in,I also used the old inlet manifold and all the sensors off the old engine because I knew they all worked,anyway,we started the car after fitting the new engine and it seemed ok,only problem is when you open the throttle it hesitates really badly like it's choking up and trying to suck to much air in,it's almost impossible to drive how it is because it's just choking up! If you keep your foot down it will rev eventually but not until it's coughed and spluttered a bit! There are no fault codes coming up on the diagnostic machine,no vacuum leaks or anything like that,we've changed the coil pack as well as other various sensors,inspected the inlet manifold for cracks too but can't find anything wrong! No engine light on or abnormal temperature readings either,when sitting there on idle the engine will be idling rough one minute then will just change and be sweet as a nut! When it does eventually rev hard it doesn't smoke at all,we've also replaced the cat as we thought it may be blocked! We really are stumped on this one! Anyone had a similar experience or know of any other reason why it would run like this? Any help would be massively appreciated!