Fluctuating idling issue

Every so often while idling at a light my trucks RPM's will drop from their normal rate of 600 down to 400 and the truck will start to run pretty shaky. If I shift to neutral and then back to drive everything would return to normal. Today at a light my truck dropped to about 200 RPM's very quickly and started running really rough. I put it in neutral and then drive like I usually do after which the power steering cut out and the accelerator would not work. The engine didn’t rev when I pressed the gas and no check engine light came on. The car seemed to be acting like the engine wasn’t on even though it was still running. I had to force the wheel so I could pull onto the shoulder and shifted to park. I turned the truck off and on again and it ran perfectly. I do know of some electrical issues that stem from the previous owners crappy DIY remote start install which seems like a good explanation but I just don’t have enough general mechanical knowledge to confidently say that's it. Just wanted to get some other opinions about what it could be and how difficult it would be to repair. Thanks