My car has 69,000 miles on it. I have an offroad H so I can see everything that comes out of my engine. A few months ago it started to puff a little blue/blackish smoke (Im not completely sure of exact color) after it had been idling for over 5 minutes. Now, it has progressed to puffing BLUE smoke at idle, and sometimes at part throttle. Before it was just every once in a while but now it does it all the time. What can I do to figure out whether it is in the engine or heads? I am thinking/hoping that it is a valve guide/seal proble, which is a good excuse to get some ported/cammed ones. I have changed the oil and ran sea foam thru it, which did not seem to help. I intend to check my plugs, do a compression test on each hole, and then do leakdown tests. Oh, and there is no blowby past the pcv. Any ideas?