Order some good coffee. 80% of your problem will go away. As I mentioned earlier, it sounds like stale (or bad) beans. If you go to the Resources page there is a column for Commerce. Any of the roasters in that list would be a good place to start. Order at least 2 pounds of a single blend, not a pound of this and a pound of that. You will need two pounds of the same blend to give you enough coffee to learn, play, and enjoy. One pound will go to quickly.

I agree with the "old coffee" diagnosis.

In our Whole Foods, the date on the bins is not a roast date - it's a "fill" date. The roast date is weeks or months earlier. So the bins of coffee are more or less useless for espresso. I did once email Allegro coffee, one of the suppliers for Whole Foods. They said

If you buy your beans in bulk from the bins, Whole Foods Markets are supposed to have "freshly filled" stickers on the bins with the date the bin was filled with that batch of coffee. They are only supposed to keep that particular batch of coffee for 1 week from that date. If you see it in there longer, it is most likely going stale, due to air exposure.

All of our coffees are packaged with a freshness date 120 days out from the day it was roasted. This includes the bags the stores pour into their bins and our packaged coffees on their shelves.

So you can subtract four months from the date on any bag of Allegro coffee to calculate when it was roasted. If you buy a sealed bag, you can produce drinkable espresso in the first 20-30 minutes after you open it.

I found a great local roaster (http://ozocoffee.com/), so I can skip this process. Keep looking!

I've ordered counter culture and black cat coffee today. Some high quality fresh beans should really improve my shots and remove most of my problems. I want to see lots of crema in my shots. The beans from whole foods must be stale because they really stink, they must be my problem. I would be really disappointed if it was brewtus or vario. I hope it is "old coffee" that's the culprit these shots are a crime.

Well I found a local roaster who seems very good, Highland coffees, and picked up half a pound of "traders blend". The guy roast all his beans in very small batches every day and labels every bags roast date, so I know these are very fresh beans.I have solved the sour shot problem, my new shots taste great! But.... I'm still not getting a lot of crema. The crema has a very nice color but is still thinnnn. Do I need to check anything with my machine?