Just replaced the IAC on mine last weekend. Scanner found my problem but as mentioned above, do a visual inspection of the IAC. When I removed mine you could see the internals melted. I found the part locally $150 and 5 minutes to replace.

Is it beeping every two minutes? If so, that's probably the code for the IAC causing the beep. Go ahead and buy an IAC and replace it, BUT BUY THE SCANNER TOO.
www.rinda.com is the right tool for the job, or you can buy the Diacom software for a laptop. This has been discussed dozens of times on here which you can find a search.

It's good to have a spare IAC on hand, which is why I said go ahead and buy it now.

Thanks for the advice guys. I'll go ahead and change it so that will be one less problem I'll have to deal with for a little while. I definitely agree that I do need to buy a scanner. I just bought the boat so I'll be having it for a while.

They not only melt, but in a salt water environment they rust and lockup the plunger, some times you can exercise it and by some time.

Mine didn't melt, just went bad. I did see on an auto repair show that you can clean the IAC with brake cleaner to free up the plunger.

As mentioned, a scan will show a flat line on IAC activity is that is the issue.

There is a picture of the melted plastic in this thread.
http://http://www.offshoreonly.com/f...r-running.html

First one I bought from merc for$150. Second one I bought from auto parts store for $30. I think it fits older ford Aerostar van.

Thanks for the help guys. I changed the IAC Saturday and it fired right up with no prblems at all. I did see what everyone was talking about in regaurds to the "melting" of some of the plastic. Thanks again for the advice.