My 2003 is bogging down with no power. Showing codes P0032 and P0038 have replaced the fuel pump assembly, spark plugs ,coil pks bypassed the O2 sensors rewelded the exhaust where the Cadillac converts where took out.truck is still losing power at about 35 to 40 mphs what could possibly causing this problem

 

Unplug the O2 sensors, see if it runs any better.

 

I have and it still starts bogging down

 

Two potential causes for your problem that I think of right away:
1. PCM may need to be re-programmed, or,
2. Removing the catalytic (aka Cadillac) converters may have reduced your exhaust back pressure to point it is affecting performance. Take a look at some of the symptoms of exhaust back pressure problems and see if you have noticed these problems in your truck.

 

I did have a exhaust leak bit had the exhaust rewelded it is doing better but still bogging down after it runs a few minutes I when about 4 miles today its like something is blocking the fuel steam .I put a new fuel assembly on it .I don't know what else to do???

 

Getting any codes? Is that a throttle-by-wire system?

 

Idk if it's a throttle by wire system only error code is P0032

 

Probably should replace the sensor. (bank one, sensor one.)

Have you checked fuel pressure?

 

Check fuel pressure at rail ,,and if muffler is still there could it be clogging up or resonator if it has one,,check air filter to see if its dirty , make sure it can breath ,,look for vacuum leaks that can result in power loss ,,clean the throttle body and check spark plugs ,,
P0032 = The ECM detects the O2 sensor heater circuit high and could enter failsafe mode until the ignition is cycled off.... power loss being a symptom,,perhaps the ECU is causing the issue like a limp mode