I think I may have won my battle with DTC code P0015! Cleaning the front solenoid worked for about 50 kms, so today I decided just to replace it with one of a pair I got off of eBay (only about $70 for two!). Here are some pictures of the procedure and a few things to consider if you want to do it yourself.

1. I learned from trying to clean the solenoid, that some oil does come out, so I put an old t-shirt underneath the catch any oil and catch the bolt if it fell (I didn't have a replacement if it did fall, so i was paranoid about that happening);
2. Removing the electrical connector isn't terribly intuitive. You have to pull UP and OUTWARD on the tab (I used a small screwdriver) and it will release, but by looking at it, it seems that you have to press something IN to release it;
3. The 10mm bolt that holds the solenoid is in an awkward position, made worse by the location of the dipstick. I used an extension about 4" to reach it. It's best to loosen the bolt with your socket and then by hand with extension and socket, remove it. To avoid it falling out of the socket, you have to sort of angle it upward and you should be able to get it out without falling;
4. Putting in the new solenoid is pretty straight forward, just start threading the bolt by hand and it will stay and then you can tighten with the socket;
5. I panicked when the connected didn't fit AS snuggly as the original part, it required a bit more force to connect than the original and I thought maybe the part didn't fit. It doesn't "click" in as solidly as the original but with some force it connected securely; I'll have to keep an eye on it, but it seems secure now.
6. After half a day of driving ... SUCCESS!!!!! NO MORE P0015 - knocking on wood .... will report back after more kms driven .....

If this fails, I have the rear (intake) VANOS that I'll do (was getting less frequent P0012 codes) and then I'll add the newer timing chain tensioner while I'm back there... then if all that fails, I'll be bugging everyone for timing chain replacement suggestions .... lol ....

 

Good job

 

HAPPY UPDATE: 6 days later, still no CEL!!!!!! (A record since bought used.) Take that P0015!

The pessimist in me thinks it may just be the warmer weather ... lol ... knocking on wood ...