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disconnect battery to clear the pcm...might have to clean the TB if you havent done that in a while..

 

Update

I ended up taking my Voy to a trusted shop to have the system "smoked". The results was that I had intake leaks between cyl 1-3 and 2-4. That kinda made since I was showing a idle miss for cyl 1 & 2. I bought a good inch-lb torque wrench and did the work myself. I cleared the dtc faults and have driven about 100 miles and no more problems except my emissions readyness has not yet reset yet and I'm due for inspection. Any thots?

 

I do regularly run injector cleaner....also have cleaned MAF a couple of days ago. Another thing I remembered, My wife was coming home from work and called me to come out before she shut it off. ALL the lights on the dash were on .no gages, and the radio was on and off.I plugged in my scan tool and it would not connect until I shut it off and then back on. It has only done that 1 more time,but the odd thing is it seemed not to change driveability. Thank's for your help !!

 

If you are getting an occational misfire along with the two codes, I would lean toward the second bulletin that I'm posting. Here are a couple of bulletins for your review:

When diagnosing 2004 and 2005 Trailblazers, Envoys and Rainiers that are equipped with a V8 engine and exhibit LEAN CODES P0171, P0174 AND MAF CODE P0101 technicians should determine if the air filter has recently been replaced.

Certain air filters, including some supplied through A/C Delco as part number 19114119, can cause LEAN CODES P0171, P0174 AND MAF CODE P0101 in V8 Equipped Trailblazers, Envoys and Rainiers. These A/C Delco filters, P/N 19114119, can be identified by the black color rubberized end pieces on the filter.

Air filters from GMSPO which do not cause lean codes for these applications can be identified by their colors and part numbers as well. Orange colored rubberized end pieces, which some people see as pink or peach color, as well as light Blue colored end pieces are sold through GMSPO as part number 15036141 and are not known to cause the lean driveability codes previously described.

Although the AC Delco part numbers have other usage and apparently perform without incident in other applications, if a lean driveability code P0171, P0174 AND MAF CODE P0101 is encountered in a V8 equipped Trailblazer, Envoy and Rainier, confirm the vehicle has and orange or blue color air filter rubber P/N 15036141 before proceeding with the diagnosis.

Cause
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.

Correction
Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline . For further information on Top Tier detergent gasoline and fuel retailers, please refer to the following Corporate Bulletin Numbers:

Notice: GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Upper Engine and Fuel Injector Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.