drove my FD several times today, performing perfectly. On my final trip out i found it was difficult to start, sputting and missing. after a few attempts i managed to get it started but the rpms would just continually fall to just under 500rpm, occasionally dipping down low enough to light up all the warning lights, and sometimes dying. I got the car on the road and warmed up. all the power is there, no smoke, etc. But the idle stays low, barely keeping it going. Where should i start looking for the problem?