i have a 2000 blazer 4x4 2 door 4.3 and the long term fuel trims are at 15+ and the short fuel trims are at 0.0 at a hot idle, my wife has a 2002 blazer with the same engine in it and i scanned it also and wrote down and compared ALL the information and her trucks long and short term fuel trims were all at 0.0 at a hot idle, her truck runs very well with no issues, MINE has no throttle response for about a minute after a cold start after the truck has sat for 4 or 5 hours, AND has lack of power and also seems to have a miss up to about 1200 rpms and seems to go away, i cannot find another thread here nowhere thats like my problem please help!!!

 

This indicates that the PCM is trying to richen up the fuel mixture. It is reading a lean condition and has adjusted a ton more fuel into the engine. This could be caused by a false lean condition where an exhaust leak between the engine and the upstream O2 sensors is allowing more oxygen into the exhaust. Or it could be a vacuum leak.

 

ok ill check i think i may have a small exhaust leak on bank 1 side but not sure cause it sounds like a lifter at idle but it get loader and sou nds like its exhaust when i punch it to accelerate, anyways thank you very much, ill let you know what i find!!!!!!

 

Let us know! Feedback is a beautiful thing for forums like this!

 

i just saw a thread about the balance shaft setting off the knock sensor, im almost positive im hearing lifters but anyways could the shaft cause a timing issue which im return cause a over fueling also in the long term fuel trims??

 

That issue should not cause the LTFT to be so rich. Also, it should be readily identified by monitoring the knock sensor output using an appropriate scan tool.

 

ok ive checked for exhaust leaks and found NONE. i replaced a couple of vaccum lines that were questionable and searches the map sensor and ALL vaccum lines but could not find a leak, i isolated each vaccum circuit and found no change, what should i do next??

 

Are the long term fuel trims the same side to side?

 

if you mean BOTH long term fuel trims then yes they are exact at idle 15+ and both short term fuel trims are 0.0 to 0.8 at idle

 

By side to side, I mean bank 1 and bank 2.

Have you tried running the engine and tracing over all gasket surfaces in the intake side of things with an unlit propane torch? If you do this and hear a change in the engine sound, then there is a leak somewhere in the vicinity of the torch nozzle.