eCart Inconsistent Results

I have had my new site up and running for about a month and am still having very inconsistent results using eCart and the authNet AIM option. Out of 119 orders we had 65 successful transactions. I did have my confirm page set up so that the orders were recorded in our DB before processing the transaction which is how I know how many did not go through. I thought the order of my code may be the issue so I have switched it back to send the data through authnet before storing it in the database but have had no luck with getting consistent results. It seems like it may be an issue with connecting to the authnet site from my confirm page. Sometimes it works just fine and then other times I get no response at all. The times I get no response at all, my full request is complete but nothing is returned. I'm stumped on how to fix this issue but we have had many unhappy customers because they are having trouble at checkout.