Trouble with top layer using PETG

So I have a TAZ 5 printer and mostly print ABS. I just bought a roll of PETG to try out and while the print looks really good the top is horrific. I used the same basic settings I use for ABS except the temperatures.

.35mm nozzle
bed 70c
hotend 240c, 235c
10% infill
Perimeters 3
Bottom Layers 4
Top Layers 6, 8

So on the left cube I thought it looked a little hot and maybe not enough layers so that's when I printed again a 5c cooler and 2 extra top layers but it came out even worse. I just tried again with at 245c 8 layers and it looks the same as the one on the right.

So, do I need the cooling fan on or something?

The only other issue is the left cube has a very slight elephant foot otherwise the sides are straight and smooth, the bottom is perfect looking.

I just tried with 40% fan after 2nd layer and same results

In my experience PETG doesn't bridge that well, especially without a fan. 10% infill isn't much for the solid layers to grab onto, so try cranking up the fan to 100%.

Also, it is very sensitive to overextruding, as the PETG can grab onto the printhead and start making a burnt ball of material. So perhaps try reducing your Extrusion Multiplier (I use Slic3r) or whatever is the equivalent in your slicer program. How does the surface finish of the first several solid base layers look?

IMHO and from the few tests I could do with sample pieces I have to say PETG is in the same area as Nylon when comes to being complicated.
As Robert said it really needs near perfect print settings to get good results, starting with the extrusion rate and speed.
Had similar issues with my top layers, especially on smaller parts like test cubes.
When you do the next test pay attention to the first two top layers being printed.
The first will look quite ugly on the infill but should close most of the gaps.
The second should already produce a fully closed surface that still might look a bit uneven and "bad".
The remaining layer shall produce a clean finnish.
You might have to slow down or speed up the solid infill for the top and bottom too.
The key is to get a good bons on the perimeters but still solid and continous extrusion lines over the infill area.