engine feels sluggish

[fluffybunnykiller]

Had this car for nearly a month now and although it was bought with an eye to replace rear bushes and a couple of small items it has not let me down so far.
The engine threw a 420 code the other week so had it check by a garage who confirmed either a o2 senser or a cat failiure, the code was cleared to see if it was a one of, it did come back after 50miles , so not to worried as this will be sorted , funily enough it put itself out a couple of days ago and came back last night .
now as this is a 2.l manual i was expecting a little more oomph from the petrol junkie under the bonnet but it feels flat, sure it gets to 80 but something feels not right. put the foot dwn and you should get a bit of a move on, but this is wooley.
havinbg read lots of posts would new quality plugs and leads make a diffrance?
noty sure when they last got changed or if it was cheap plugs only.
any advice would be great
many thanks

[CREWZIN]

It's always a good idea when you purchase a used vehicle to do a routine maintenance of changing fluids, new plugs and wires and an overall inspection of the brakes and undercarriage so you know what's been done and to start keeping records from then on.

If you have the knowledge and tools, a compression check, engine coolant pressure check and good inspection of belts and hoses is always a good idea too.

[fluffybunnykiller]

when i bought the car , it had a full stamped history in teh book.
had new black bits at each corner and disk and pads are recent with less than a mm on the lip of the disks, the petrol tank has been replaced at some point, and the car has that looked after feel about it that you get with one owner from new.
I dont think there any serious issues as such in the engine as it fires and runs smoothly with no miss fires or lumpiness, always starts first turn of the key no hesitation, so i think it may just be down to maybe the plugs and leads and either the o2 sensor not giving the right info to the ecu or the cat failing and allowing the o2 sensor to give the wrong info , but as a newcruizer i am aware there is a heck of a lot to learn and it could be something else altogether