I kinda had one of these recently. It’s the 200’ thing that REALLY made it hard. Thought I heard sputtering, and just FELT like I couldn’t maintain altitude, which I couldn’t.
Tried “troubleshooting” but honestly don’t remember seeing a single gage! What little I did look inside I played with the throttle and realized for what ever reason, the engine was making noise, but I couldn’t fly. Can’t remember seeing the airspeed either. I was up to about 70 degrees angle of bank to make a break in the trees, not sure what my stall speed is in that configuration, so wouldn’t’a mattered anyway! Literally just flew by feel, was glad I had experience that was relevant.
Turns out it was water. Engine never quit, just no idea how many rpms I lost, or how much power. I was VERY nose down in the turn.
One other time same thing, but I could fly... that time I could see tach, and comprehend it, just couldn’t get over 2000. Got the carb heat on, eventually fixed it. It just sounded weird, kinda like the water thing.
On takeoff roll its part of the scan for me, would like to think I’d catch it. But that sputtering, or decelerating feeling that WILL get your attention.
A little off topic. A new philosophy for me is to turn ANYWHERE, IMMEDIATELY after takeoff. The one place you want to be if something goes wrong is directly under, and unreachable by, you. So get somewhere unusable, so the useable is more reachable. Ironically, I did that on the water debacle. I made the turn from 200’ or less. Granted power loss, not engine loss, but I made 180 degrees of turn. Had no choice. But I turned immediately after takeoff for other reasons. Little uncontrolled field.