I have a 2003 silverado and am having an issue, the check engine light came on and had code pulled and was for o2 sensor, saying a short. When i first start the truck up it runs ok except at wide open throttle, it will feel like its stalling out a little but otherwise runs ok. As the engine gets warmer the problem gets worse. I took a 150 mile trip and it ran ok until the last half then I had to baby it just to get it up to highway speeds. at light throttle it ran fine but at moderate to wide open throttle it was like it was sucking air or something. would lose speed until i let off throttle. Also when engine is warm when i start it, the rpm's will fluctuate sometimes and will miss and pop if i try to take off unless i wait a few seconds then it will idle fine. I am at a loss as to what the problem is. The truck has new maf sensor, map sensor, 02 sensors, air filter and fuel filter. Anyone have any insight?

 

i was told after replacing O2 sensors that the computer needs to relearn and i should drive the truck for up to 150 miles so it can relearn.

 

the truck no longer has cats by the way

 

Well 150 miles is a little overkill. I'd say up to 10, but really it sounds like an 02 or MAF issue. Personally, I'd need to look at some engine data to get a proper answer for you, but something you can try is unplugging your mass airflow sensor. It will set your check engine light on, and maybe even reduced engine power, but the truck should run okay (I think - it might run badly too)

If she runs better, than it's your MAF that's bad, if not, then you'll need to look elsewhere for the culprit. You'll most likely need to get a scan tool and watch sensor data and see what sensor is throwing things off. The 02 sensor code is a good indication that something awry, but an 02 code doesn't necessarily mean that the sensor its self is bad. It could just mean that the exhaust is too rich and the sensor isn't switching anymore.