Fermentation slowed with no vigorous activity after a day

I just brewed my first all grain batch on Thursday. I did a single infusion mash with a batch sparge. During the initial phase of the mash I had the temperature higher then I wanted (>160 degrees for about 10-15 minutes), then only got the mash down to around 158-160 for about 50-55 minutes. My efficiency was pretty low at only about 68%. The OG was 1.042 only about 3-4 points off the intended OG. I created a yeast starter a couple days in advance and pitched it to the wort.

My problem is that I had visible signs of fermentation after about 6-10 hours with a small krausen forming. The fermentation never got as vigorous as I'm used to seeing. Now on Saturday fermentation has slowed as far as the airlock is concerned, to an almost imperceivable amount. My fermenation temperatures are not the problem as it has been between 71-73 degrees.

Did I cause the issue with the higher mash temperatures? I need to take a gravity reading still, but if it is still high should I pitch more yeast?

What was the recipe you used, what was the yeast that you used, was this a 5 gallon batch? how big was the starter? you should check the gravity and see where it is at now, it could have finished up fast with a starter..

I made a red ale using 8 lbs of 2 row pale malt, .5 lbs Weyermann Caramunich II, .25 lbs Weyermann Caramel Wheat, .25 ibs Weyermann Chocolate Rye (it's basically the Dawson's Multigrain all grain kit from Northern Brewer) for a 5 gallon batch. The starter was made with 2 cups of water and .5 cup of extra light DME, using the 1084 Irish Ale smack pack from Wyeast. I haven't had to check the gravity yet, but hope to tonight or tomorrow. Do you think it could be due to the mash conversion?

I brewed a chocolate mint milk stout using the Irish ale yeast, it fermented out in under 3 days and it was a 1.070 grav beer, I would just check the gravity, and see how low it dropped.