So I've been working on my fiance's 2006 Aveo for the past few months and it keeps having intermittent recurring issues. She's owned it for the past two years and it has 147K miles on it. Has always been a reliable little thing until about three months ago it started throwing codes and having issues. Throwing codes like P2110, P2106, P2135 mostly, with an occasional P0420. I ended up buying an OBDII reader and looking up codes online and have done quite a bit of work on the car recently, but considering the issues are still occurring I found this forum and beg your help. The symptoms of the car are: sometimes when driving she will feel a buck or jolt and then the acceleration is gone and a CEL pops on. This is sometimes fixed by pulling over and turning the vehicle off and removing the key and restarting after a minute or so, other times it takes a few restarts before it's capable of acceleration again. Other times when she comes to a stop the engine will simply stall out and die and upon restarting the car the idle will rev up and fall and up and fall while the engine seems to shudder heavily. At times she says it'll stall after the revving and then after starting it again it will be fine for awhile, other times it continues with the revving issue and is unable to drive because the rpms keep boosting up and falling. She did her own research and asked me to fix a few things in the vehicle so the work I've done so far is changing out the battery since it had a green acid foam coating one of the terminals, Throttle body (with the TPS inside), air filter and intake hose, spark plugs and wires as well as the ignition coil, new crankshaft sensor, upstream and downstream O2 sensors and replaced a half dozen vacuum lines that seemed brittle or were breaking apart. Since she's had the car for about two years now I went ahead and did a radiator flush, changed thermostat and did the oil/filter too. Also just got finished last week with the timing belt which I have to say was the most difficult PINA timing belt I've ever done. After all this I'm still getting the same issues and felt like you all might be able to help me more than just blindly changing parts out. Just through process of elimination and using codes I was curious if the alternator may not be keeping consistent voltage, maybe the battery c able harness was damaged by the battery acid, or possibly the ecu is having issues. I'm at my wits in at this point.
Any advice would be helpful, thoughts or comments as well. I'll be back in town to see the vehicle in about a week so I'm thinking of making a dealership appointment this go around since I don't feel like wasting my home time working on her car the whole time.