2003 HD stalling

[northeast SS]

Hi, I am new and have just bought a 2003 GMC 2500 HD with a 6.0.
The altenator was garbage so I replaced it . Now the truck stalls when put in gear or at stop lights. Also replaced sparkplugs,fuel filter,battery,belt and air filter.
Check engine was also on when I bought the truck. I assumed it was on because of the alt.
The truck run down the perfect for 177,000 miles and also idles fine.
Any help would be greatly appreciated.
Thanks

[03chevy]

welcome to the forum you can check this out and see

1Inspect Fuel Filter Clogged or dirty fuel filter

2Inspect Wireset Damaged, worn, or deteriorating spark plug or coil wire(s).

3Inspect Spark Plug Fouled, damaged or broken spark plug(s).

4Inspect Carburetor Float Improperly adjusted/saturated or damaged carburetor float.

6Inspect Timing Cover Stud Kit - PerformanceImproperly adjusted or worn/malfunctioning power valve

7Inspect Choke Pulloff Worn, defective, or faulty choke pulloff(s).

8Inspect Choke Thermostat Stuck or improperly functioning choke thermostat.

9Inspect Fuel System Pressure Incorrect fuel pressure being delivered to carburetor or fuel injection system.

10Inspect Idle Air Control Valve Damaged, loose, or faulty idle air control valve.

11Inspect Idle Speed Control Actuator Damaged, loose, or faulty idle speed actuator.

12Inspect Idle Stop Solenoid Damaged, loose, or faulty idle stop solenoid.

13Inspect Mass Air Flow Sensor Improperly connected or faulty mass air flow sensor.

14Inspect Throttle Position Sensor Faulty throttle position sensor or throttle position sensor circuit.

15Inspect Electronic Spark Control Module Faulty spark advance system or system components.

[leolkfrm]

sounds like a partially open egr valve creating a vacumm leak. Did you put a scan tool on it? It might give a better indication of the problem

[northeast SS]

I Havnt put it on a scan tool as of yet.I am trying to find a reason for it before I drove a hour to the dealer to have him tell me it was something Idid when I changed the alt.

[leolkfrm]

double check your wire connections maybe one is grounding out. check the battery connections and make sure the cables aren't rubbing somewhere

[tjzz4]

go to autozone and they will pull codes for free

[northeast SS]

I had garage put it on a scan tool last night and there is no data reading at the plug.
Nice ,sounds like I have an electrical problem somewhere. Finding it will be the fun part.

[leolkfrm]

sounds like a blown fuse, does the cigarett lighter work? usually thats the circuit that acts up for scanning. double check all the fuses if that is not it.

[northeast SS]

Thanks guys, I found burnt wire on the rear o2 sensor and ablown fuse for the cig. lighter. Also found
a bad wheel bearing that cost $300.Thanks again guys. Ill bein touch
Kevin

[mudseeker]

$300? please tell me that's with the labor cost from a shop. i think it cost me around $150 for a new hub on my truck.