2002 Stratus - jumpy speedo/tach, racing engine

Sometimes when I start my car, the engine will immediately start racing, and the speedometer and tachometer needles just go crazy. Obviously I can’t shift into gear while this is happening, but if it stops long enough for me to shift, the car is usually fine and it doesn’t happen again while I’m driving. Today the same thing happened to me, but while I was in reverse, and it would not stop doing it. While the car was moving, it was very jerky, just like the dials. When I put my foot on the brake, the car felt like it was pulling at the bit, so to speak. I didn’t try putting it in drive, except to pull back into my parking space, and it behaved normally that whole time. It makes me really nervous and I’m not sure I want to drive it like this, clearly it wouldn’t be good to accelerate randomly into the back of someone. Thoughts?

There has to be a CEL illuminated with this condition. If not, I’d suspect the PCM. That’s too much of an anomaly to NOT throw a code.

The light is on, but the codes it gives are related to emissions, which doesn’t seem like it could be related to me.

Which are they?

The ones I have gotten are P0442 - Evaporative Emission Control System Leak Detected (small leak) and P0455 - Evaporative Emission Control System Leak Detected (no purge flow or large leak). It also sometimes, but not always, gives P1684 - Battery disconnected within last 50 starts (but it definitely hasn’t been).