Yes, women with PCOS often also have insulin resistance, which impedes or even prevents ovulation. You can't diagnose insulin resistance just from a standard blood sugar test, you have to have a glucose tolerance test done. But that's why they often prescribe metformin for PCOS, because it helps control blood sugar and can help ovulation.
The best thing for insulin resistance is to follow a lowish carb/low GI diet, so cut out as much refined sugar as possible, and stick to wholegrain carbs (but not too many). Lots of lean protein and vegies.
I don't have polycystic ovaries but I do have insulin resistance. Since I've been on metformin and changed my diet I've lost 10 kg and gone from barely ovulating on my own to ovulating like clockwork, even a little early. No bfp yet but I'm hoping it won't be long.
Since you know you have PCOS you should talk to your doctor about treatment options, but just changing your diet can make a big difference.