Dull patches on non clear coated red

When the sun shines on my red car i see dark patches that look as though there is dirt ingrained into the paint.The car looks great until the sun gets on it then these patches appear usually on the large flat areas.Ive used Meguires body scrub but it doesnt seem to of moved them.It seems deep in the paint.
Should i get the buffer out and use something more abrasive or should i keep applying the body scrub until i get down to a clean layer of paint?



Red is the best!!

sounds like the high speed is in order. what kind of car? Some old German cars that don't have clear on them, have more layers of paint, so you have some mils to work wilth while buffing. I did an old Porsche (red also) that was heavy oxidized and it come out great. Using the less is best technique first, I had to start with a wool pad and compound, (low rpm 1200-1300) then go to green pad and glaze (polish) at about 1750 rom.....and finish up with p21s (which is my favorite wax for german cars now, thanks to this board) it came out fine, but you may to get a thinkness gauge if your base coat is too thin. good luck....tm