I've had the notorious rough idle when cold for a while now. I finally put in new intake manifold gaskets and expected an "easy" fix, how wrong I was. It didn't solve the problem at all!

On the plus side the computer is now showing a failure on the left intake air temperature sensor, we'll see if that fixes the problem. It's interesting, I can feel the ECU adjusting things as the engine will pull hard then hesitate then pull hard again as it plays with the timing and such...

Anyone else have this sensor fail? I've been perusing these forums for a while now and haven't seen this part mentioned before...

replace both of them (they aren't expensive) and you might also take a look at the three water temp sensors on the passenger rear side of the engine - now those are a bitch to get to, but do improve the engine running characteristics.