Radiator and thermostat were replaced; also an oxygen sensor was replaced. After those repairs the car stalls as soon as I start it. (starts and die right after). If the MAF sensor is unplugged the car will run but the engine won’t go over 2,500RPM approx.. Replaced the MAF sensor and still having the same problem.

2005 350Z, 35th Anniversary

 

Did you replace the 02 sensor and MAF sensor with OEM or aftermarket parts? If aftermarket, which brand?

You may need to do a relearn on the MAF. Unplug the battery for an hour and then drive the car around for about 20 minutes or so. See if that makes a difference.

EDIT:
Does your car have any engine mods that would affect airflow?

 

 

No mods other than the intake

 

The intake was longer than that, the guy working on the car broke some plastic part and fix it like this. May the intake be the problem?

 

AEM filters are supposed to be orange. That's either the dirtiest air intake filter I've ever seen or it's some other brand that (stupidly) decided to color it black so you can't see how dirty it is. Those types of filters can be cleaned, but they also need to be oiled, and the oil can gum up and ruin the MAF sensor.

Try to stick with OEM on the sensors (particularly the MAF, CPS and Knock Sensors) and avoid Autozone parts for your Z unless you're talking about oil filters or whatnot. If finances make it impossible to go that route, then I'd go with a guaranteed OEM junkyard sensor before I'd go with a product made by a company like Dorman.

I'm not sure who makes the OEM O2 sensor for the Z, but the NTK O2 should be okay, as long as the voltages are close enough to factory not to trigger any PIDs.

RE: The intake, you're going to get a lot more hot air going into your engine than you would with a factory intake. Nissan did a good job with the factory air boxes and I'd recommend going back to one of those if you can find one. The AEM looks nice, but you're actually hurting your engine's performance.