Oh Todd, pressure washing and awning cleaning are not the same thing and one should never pressure wash a vinyl awning. It blows little microscopic holes in the awning and prematurely degrades the surface. Ask me how I know.
To answer the first question. I am quite versed in the cleaning of awnings how can I help?
Too much pressure will cause tears and scarring to vinyl, but you can pressure wash awnings by:
1. Scrub the awning with a brush and rinse with very low pressure from your pressure washer
2. Brush a mild detergent over the surface of the awning and leave it to sit for a few minutes
3. Rinse with a low PSI but high GPM using a very low pressure washer nozzle
4. Apply a sealant to keep colors from fading - for a bonus use a UV-ray sealant to protect from sun damage
5. Repeat every quarter to keep the awning looking great