Hi, I've got a somewhat intermittent issue that I am able to reproduce if I get it just right.

The car has a slight stumble or dip in rpm (right at tip in) and if the gas pedal is pushed hard and kept down right at the time of the stumble then the engine is likely to not rev up. It loses power and won't rev over 1500rpm, even in neutral. It will stay up around 1500rpm with the pedal on the floor and maybe backfire every 5 seconds, it seems to be running rich but the exhaust doesn't smell rich. If I let off the gas pedal completely the engine will sputter along around 500rpm for a few seconds (never dies though), I can then poke the pedal a bit and the engine will rev up and start running normally again. 99% of the time the car runs completely fine.

I cleaned the throttle body which improved the idle but the problem is still there. I checked the throttle position sensor and it clicks just off idle.

The only code I'm getting is 3-1-1 which is "vehicle speed signal missing).

Any ideas where I should look next?