S60 T5 partial power loss

[Hayne]

Hi,

I am new to the forum due to buying my S60 T5, which I love driving.

A few months ago I noticed the car jerking (kangarooing) on light throttle when cold, which disappears when it gets warm. The car has always idled perfectly.
I read on the forum about faulty electronic throttles due to wear on the potentiometer tracking. I checked mine out and luckily, it is the Bosch model, so shouldn't exhibit the same issues. I removed it from the car and cleaned it thoroughly, reassembled it and it made no difference. Could the TCM still be faulty or is this unlikely.

Also, another symptom is when driving at any throttle position, there is a slight loss in power, as though there is intermittant boost, but I am not sure if it is turbo related as it does this at 1000rpm too where I wouldn't expect boost issues. It is most noticeable at high revs when the turbo is spinning where the car seems to pulse it's power from about half power to full power every second or so.

Yesterday I noticed it idle rough for about 1 second a minute after I started it too.

I have checked the coil packs and found one brown pack, which I replaced, but there was no difference.

I also changed the MAF, again with no difference.

I removed the TCV and cleaned it, but again no difference.

I checked the pipes for splits and couldn't find any and all pipes appear to be well clamped down at each end.

I read the codes using my OBD reader and there are none there.

Does any one have any idea what my problem might be as I don't want to spend any more money on non faulty parts and it is frustrating when the car looses power. When I don't see the fault, it just flies like it should with loads of power.

Sorry about the long rambling message.

Many thanks in advance.

Cheers.