S3 running problems, maybe?!!

Hi guys, had my S3 for about 6 weeks now, it's a 2003 bam completely standard. I have noticed in the last few days it doesn't seem to pull as well as it did when I first got it, could just be me getting used to it I suppose but definitely doesn't feel as quick...

Also I noticed that a couple of times, since replacing thermostat it seems to struggle a bit to start when engine is already warm, when I say struggle I mean it turns over a bit longer than usual before firing, always starts though and only done a few times.

Just wondering if anyone can think of anything obvious I could check myself or is it a case of having to get it plugged in? Which will mean a trip to audi main dealers unfortunately

Thanks guys!

Thanks for your helpful reply Chris, I thought that may be the case.

Tbh I'm starting to loose faith in this car already there always seems to be something wrong with the ****** thing!

Thanks mate, I was planning on driving back to the uk in the summer and was going to get a scan and a big service done then, would be much cheaper than getting it done here, but I can't wait that long if she's not performing properly!