Problems with my 01 Sierra

OK, i go to the store and my truck is working normally (except with the engine check light on). I get home and about an hour later I get in my truck and I turn the key and NOTHING happens. So, i turn it back to accessories and the radio works fine so I'm thinking its not the battery. A few minutes later I try and start the truck with my remote start. That DOES work..BUT.. when i go and step on the brake to put it in drive all my gauges stop working. So, I put it in drive anyway to get it back in my garage and about 85-90% of my power is gone. I had to really step on the gas to get it over a 2 inch incline. Whats going on?

go up to your local autozone and ask to see if they can read what the ses code is (they usually do it for free) i dont know how long youve had it on... but if it isnt that then you have just eliminated one possiblity...

how long ago was your remote start put on cause some of the 99 nbs and up there is a wire that if it isn't hooked up right it will send your tranny into a stupid mode i think it is the second ignition wire if it isn't hooked to the specifice second ignition it will do that i would just take it to who ever hooked it up and tell them what it is doin and they should know