So this morning while driving to work, I was behind a driver who was going 45mph and they sped up to the 55mph limit and so I attempted to speed up behind them and my car decided not to accelerate anymore. It was in 4th so shifted down to 3rd to see if there was any difference and there was none. Put the car back in auto and pulled into a driveway to turn around as well as to shut off and restart the car. Cranked it again and it sounded hesitant to start. Shifted to reverse and acceleration in reverse seemed normal for the 3 seconds it was in use. Then back to automatic Drive and no acceleration, and mashing the accelerator made the car make a clunky grinding noise. Only error codes were P1800 (VIAS) and P0430 (cat error). I could only get up to about 15mph, basically couldn't tell the accel had any affect on the car's speed. Parked somewhere and used a 10mm socket to disconnect batt terminal from post for 1 min and reconnected, car runs fine now. No Low Fuel lights. The car sounded very physically damaged, very clunky like there was a wrench stuck in the rim or something lol, but the battery reset trick magically fixed it. What could this be a symptom of? Alt is new, radiator is new, sparks and coil packs are new, oil is within range. I know the problem isn't solved, just dormant! Any ideas?

 

Tough to say. Address the codes and go from there. If your cat substrate is busted up and rattling around in the exhaust, that would be very bad.

 

I should also say the ECM is new too. I dunno what the issue is because I can't imagine the cat misbehaving would 1) disable acceleration or 2) fix itself after the battery was unhooked. Because the thing is, the codes didn't clear out with the battery disconnected. The SEL was instantly back on. But the problem itself was fixed. I dunno man, it's got me *stumped*

 

But you do know what the issue is. P0430 is pretty common, and could be the reason you're running erratically. Address the codes before wasting any more time speculating.