last friday my truck would die when I would put it in park, not everytime but very close to. I wasn't sure what it was so I went on here and everybody said it was probably the IAC, so I went to Autozone and got a Duralast IAC that came w/ a gasket. I installed it and it worked great, the truck would no longer go under 500 rpms when put into park or nuetral at all anymore. So I figured I would return it and save $3 and get a motorcraft IAC from rockauto.com. I put that in and it doesn't run as good. I mean the truck doesn't die but it comes relatively close w/ the motorcraft IAC which is strange because I thought I was doing the truck a service by putting a motorcraft part on it. the motorcraft IAC did not come with a gasket but I kept the one that I got from auto zone.... so I reinstalled it the motorcraft IAC w/ the gasket.... runs a little better but not nearly as good as the duralast IAC from Autozone. Did I get a no good Motorcraft IAC or are the duralast IAC better quality, or was it just a coincidence that the IAC from autozone was allow the truck to run perfect and there is really something else wrong w/ the truck? i'm tempted to return the motorcraft IAC and re purchase the Duralast IAC. Any Suggestions would be great!