We have a 2000 CRV with 138K miles. I set the valve clearances about a month ago, and now after about 1500 miles it is running rough at idle, seems to smooth out some at higher revs, but 'check' engine light flashes. There is also a very high pitched whistle (vacuum leak??) that I can barely hear, but I do have hearing aids and some loss at high frequencies... Any ideas out there??
There is also a heavy ticking sound like maybe a rocker arm tapping.
John & Sue