code 43 & 44
 

I am having some issues with my fuel system, I believe. I pulled code 43 & 44 off the computer. Should i replace the ecm, the o2 sensor, or what. I can drive no problem and then it feels like it is loading up on fuel but will only go if I let off the throttle. I can turn the truck off and turn her back on and she will run fine... for a while. Any thoughts. Thanks for the help guys.

43-
ESC circuit
knock sensor signal

44-
O2 sensor (lean exhaust)

O2 sensors from Rock Auto are 'bout $17.00 so it may be worth a try but I'd wait til somebody, ahem, who has a better idea. From what I found a failing Catalytic converter can give the O2 sensor wrong readings as well.

i changed out the o2 sensor and reset the codes. it doesn't look like this has fixed the problem. it is also popping coming from under the hood now. HELP!

I would concentrate on the ESC code. A code 43 can be caused by a faulty connection at the knock sensor, ESC module or ECU. It can also be caused by a CKT 485/457 short to ground. CKT 485 (or 457) is a black (or yellow/black) wire which runs from the C cavity on the ESC module (center pin) to the B7 terminal on the ECU. The circuit # and wire color are body dependent, but I cannot tell you what color yours should have. That is why I listed both.

As far as what the ESC module does... Electronic Spark Control (ESC) is accomplished with a module that sends a voltage signal to the ECU. As the knock sensor detects engine knock, the voltage from the ESC module to the ECU drops, and this signals the ECU to retard timing.. The ECU will retard the timeing when knock is detected and RPMs are above 900RPM. Code 43 means the ECU has seen low voltage at CKT 485/457 terminal "B7" for longer than 5 seconds with the engine running or the system has failed the functional check.

Basically, the ESC module is somehow not passing the proper voltage to the ECU for normal running and the ECU is retarding the timing as a result. Because the voltage is so low from the ESC module, the resulting timing is having a serious impact on driveability.

cap and wires
 

Thank you guys for all of the help. I talked to a chevy mechanic buddy of mine in so. cal. and he told me to check my cap and wires. I pulled the dis. cap and cleaned it up. My truck is running perfect. I don't know if I said it before but it started "popping" lately and now it is running fine. Thanks again for all the help. Hopefully this may help somebody else too.