Toyota Repair: valve problem, valve job, valve adjustment

Question
At 87K miles my '00 4runner w/2.7L had a vibration at idle and check engine light. 1st mechanic said #3 exhaust valve was burned and recommended a valve job. 2nd mechanic noted that #3 exhaust valve was tight and recommended an adjustment (1st for the engine). Had the valves adjusted, fast forward 20K miles, have vibration at idle again, no check engine light. Am taking it back to mechanic #2 next week. No other symptoms other than the vibration. I'm fearful of an expensive valve job. Can you shed any light on this; cost, other items to replace when doing a valve job, how common this is, could it be from my neglect of getting a valve adjustment at 60K miles? Thanks in advance.  

Answer
The valve adjustment is somewhat critical on these engines and valve problems common if not adjusted, mechanic #2 was correct in at least trying to help with a valve adjustment, I have done so myself with good results without doing a valve job, it depends on the valve condition, if it was just tight there will ne no problem but if it has started to burn then the valve adjustment may only be a temporary solution. These engines also have a n issue with fuel injectors, what I would recommend doing is to have the engine compression tested, if the #3 cylinder has low compression then it's time to do the valve job, if the compression is good then I would consider replacing the fuel injectors or at least the one on #3 cylinder. I refrain from giving cost estimates because it varies a lot with locations and who is doing the repairs.