recently swapped ls1 for ls6 intake and my ls6 did not come with a map sensor so i used my old ls1 sensor but it was kinda loose in there. i put some rtv sealant in there and when i hooked the sensor up to the clip it was really hard to get in. is there a difference between ls1 and ls6 map sensor? basically when my car is idling it will idle normal for awhile and then surge up to around 1500 and come down very slowly. i am pretty sure there are no other lines caught under the intake but i did not replace the intake gaskets. what should i look at first?
thanks

 

It sounds like a vacuum leak to me. Get some starting fluid, spray it around the edges of the intake, and around the map sensor area. If you have a vacuum leak, the idle will speed up when it sucks the starting fluid in through the leaky seal. It will let you know for sure if you have a leak, and help you pinpoint where the leak is.