Smoke from exhaust and loss of acceleration on the highway

Hello, do you know the Sub-model for this vehicle? GLE, GXE, SE, XE? Big clouds of white smoke like that sounds like it may be a fuel injector that is either stuck open or the ECM driver for it has shorted out and is keeping the injector on all the time.
What you can do is while its running, unplug each injector one by one, so unplug one see if it stops smoking and plug it back in, then go to the next one, don't leave them unplugged. This is just to check if it's a driver issue, a wire issue, etc. Keeping one open.

Okay, or did you unplug a sparkplug wire? I see this car has a distributor system. Here are the wire colors for the fuel injectors

Don't touch a sparkplug wire while the engine is running, you'll get a bad electrical shock

Okay, so I see this code p1400 is the EGR and canister control solenoid valve, the canister is part of the Evap system, which is a sealed system that takes the fumes from the gas tank and purges them into the engine at a metered rate. If that solenoid is stuck open it can cause a rich condition as well. Meaning too much fuel is getting into the engine. I would replace that valve first, and then see how it runs.
It's odd that this system would have the EGR and evap system combined like this. But that's the way this one is built. An overly rich system can definitely cause white smoke like this, that's why I thought of an injector first. I didn't realize that solenoid controlled both systems. After you replace the valve, erase the codes and give the car some time to burn that extra fuel out of the intake manifold.