[enslow]

Good to see you here too! Well, you know my answer about the smoke. I don't think your oil burning is all that severe for now, but I understand you don't want to replace O2 sensors until you know what to do about the oil.

1. I think the first thing I'd take care of is the exhaust leak.
2. Because you are getting a misfire at cruise, I'd check your MAF voltage.
3. You can check the function of the O2 sensors with a voltmeter. It should switch from 0.8V to 0.2 volts at least once every 3 seconds.
4. I might hook up a vacuum guage to the EGR vacuum line and see that (a) you have no vacuum at idle and WOT and (b) you have partial vacuum to the EGR at mid throttle.
5. Manually apply vacuum to the EGR while the engine is idling. You should hear the engine speed drop. If not, you are not circulating EGR gases and have a fault in the EGR system.
6. When you fix the coolant leak, pull the valve covers off and change the valve stem seals at the same time. It can be done with the cams in place, and if you've got the skill to change cams, seals should be a cinch! The other thing I'd do at the same time is make sure the tapets are cleaned and moving freely before reinstalling.