This last year my perfectly running 2010 Aveo, with 218,000 miles on it, has been plagued with problems. I change the oil religiously & it burns just under half a quart of oil in 3500 miles. I do all my own maintenance and replace parts with OEM components whenever there's a problem. It's been a great car. But the past 10 months or so have not been kind to it. Typically I can troubleshoot and fix anything but these have me stumped.

Here is a run down of issues:

First problem:
Needed new rims as the tires kept loosing air.
Tire company replaced them with plain steel aftermarket rims.
Tire Pressure Sensor light would not go off even after several attempt to sync the sensors.
Was told the batteries in one of the sensors was going dead.
Replaced them all.
TPS still will not sync and the light is on all the time now.
I was told the ECM could be failing.
Note:
I can't put the wheel covers on as the rim shape is different.
Question: Could aftermarket rims screw up the signal? (I doubt it but thought I'd ask)

Second problem:
Engine started occasionally misfiring under light acceleration when traveling at speed.
From a standing start, smooth acceleration until about 3rd gear... then misfiring would start (again occasionally)
Let off the throttle and it would smooth out.
This has gotten progressively worse but still intermittent.

Third problem:
If I hit the 'Hold' button (when misfiring occurs) the transmission will down shift, engine RPM goes up and acceleration is smooth, far less to no misfiring. However within the last 700 miles when I go to turn the 'Hold' button off the transmission will not shift into the higher gears.
Shut the car off at a stop light and start back up and it shifts fine but the misfire returns.

Question: Could these symptoms be a failing ECM as stated earlier or is it more plausible that these are separate issues?
I did read that P0420 code can be caused by leaky fuel injectors putting too much fuel into the cylinders. Perhaps?

CODES:

1st CODE: P0420 Catalytic converter
(I followed the suggestion and sparked one up / felt much better but still have the code)

2nd CODE: P0300 Misfire (expected that with the rough acceleration)

3rd CODE: P0583 Cruise control circuit Low Voltage
Question: Could this be another sign of a failing ECM and contributing to the other problems or is it again more plausible that the control solenoid is failing?

NOTE: The last code ( P0583 ) just started with the occasional and progressively worsening misfire. Maybe 1500 miles ago.


Maintenance:
Plugs are 1 year old.
Coil pack brand new 2024-04-04
Exhaust and Cats: All new exhaust 1 year ago from the exhaust manifold on back.


I hate the idea of getting rid of Bullet. But is it time?

Nemo