I have had the westers tune for quite a while and it has been perfect. This afternoon I developed a rough idle. No engine light and car accelerates and drives normal with plenty of power. I did fill up with gas this am and did not use the usual shell v power as I was running late. I did use 93 octane bp gas though.
If I was guessing, I would bet on gas related but wondering if anyone else had any ideas.
Chuck