2006 Chevy Aveo Ambient Temp Sensor and P0300 code
 

My son purchased a 2006 Chevy Aveo LS Sedan.....his first car. We checked before we bought it with the owner and the timing belt had just been changed (135k). 1k miles later and the timing belt broke and took out the motor. We now have a used motor we've installed (79k) with a new timing belt and a few other things. While we were putting it in, we replaced some of the AC parts at the same time (condenser, etc).

When we put the used motor in, I installed new iridium plugs and wires. The car ran rough with a check engine light for the P0300 code...multiple misfires. We replaced the iridium plugs with Bosch and it ran much better. I cleared the codes but we continue to get P0300 code on it. Any ideas?

The 2nd question is, when I put the condenser and radiator back in, there was a plug hanging in front of the condenser. It appeared to be a sensor at one time but basically has disintegrated. It seemed to have been mounted to the upper radiator support. Is this the ambient temp sensor? If so, what is the part number I would need to replace it? I went to a dealer and they can't even find it in their drawings so I am unsure of what to order for it. They said the car doesn't list it has an ambient air sensor. Before I put the car back on the road, I want to make sure we've done everything we can to make sure my son doesn't get stranded somewhere again.

let me start with, im sorry for your son buying an Aveo. theyre poor Korean made car that GM stuck a bow tie on. the misfire could be from the timing belt being installed wrong.
could the sensor be a collision sensor for the air bag?

We did the timing belt install ourselves and seems to be running fine. I don't think it is off and the car is running smooth. I'd think it would run rough if the timing is off.

I don't think it is an airbag sensor and the dealer didn't think it was that either.

if the timing was off even 1 tooth you would have a lack of power and idle rough.
if you put a new engine in...that has a different crankshaft position sensor...a crankshaft variation relearn must be done or the p0300 will set at high rpms.
I hope you put in a timing belt kit....that includes...new water pump, idler pulleys and upgraded timing belt...belt along is not enough

post the wire colours of the connector in question. pic would help

It doesn’t miss all the time and it seems to have plenty of power. Before we put the used motor we did install an entire timing belt kit.

on another note.......the sensor I’m trying to figure out is in front of the condenser... any idea what is missing?
https://cimg1.ibsrv.net/gimg/chevrol...1e2d13b35.jpeg

with the wire colours and knowing how many wires are in the connector; I can look it up.

the early aveo engines had valve problems. put a vacuum gauge on the manifold...if you see the needle drop out it could be valve related. goggle vacuum gauge diagnosis and it will show you what the gauge needle does during a valve problem.

The wires for the missing sensor has two wires. They appear to be orange and a brown with back stripe.

https://cimg3.ibsrv.net/gimg/chevrol...17e168620.jpeg

the colours match the hood ajar switch. Its used for models with theft deterrent and or remote start