Chevrolet Repair: 1997 tahoe loss of power between 40-65 and vibration, chevy store, o2 sensors

Question
Tahoe has loss of power and vibration thru the cab. drove it and felt like something wrong went to see if any codes popped and a low air volume code, looked and the maf was unplugged. Plugged it back in and it died when going into reverse or drive. Changed MAF and it was fine but now i sputters sometimes upon stopping and going. Went to have codes ran again and it was showing 601,603 and 607. Chevy cleared the codes and they have not come back but the powerloss and vibration is getting worse.Between 45-60 rpm around 2-2 1/2 no power. changed everything i can think of, o2 sensors, cap, rotor, plugs wires, maf. Starting to think it may be in the trans. I also put a new exhaust system on it which has no cats and its reading lean codes but i can understand that with no cats. Any help would be greatly appreciated. Thanks.

Answer
HI JEREMY,WELL THE PO 601.603 AND 607 ARE ALL CODES FOR THE ECM NOT SEEING THE THROTTLE RESPONSE LIKE IT WANTS TO..THIS COULD BE WHY THERE IS LOW POWER.THIS PCM MAY HAVE A PROBLEM STARTING OR THE IT MAY NEED TO BE FLASHED TO UPDATE IT..I AM SURPRISED YOUR CHEVY STORE JUST CLEARED THE CODES AND NOTHING ELSE...AS FAR AS THE VIBRATION GOES THIS COULD BE FROM U-JOINTS STARTING TO LOCK UP..DOES THE VIBRATION ONLY SHOW UP UNDER THROTTLE RESPONSE..WHILE COASTING THE VIBRATION STOPS ??? IF SO REMOVE THE DRIVE SHAFT AND SEE IF ANY OF THE U-JOINTS ARE LOCKING UP,, IF SO REPLACE THEM AND THAT WILL TAKE CARE OF YOUR VIBRATION... DO YOU FEEL IT THROUGH THE ENTIRE TRUCK OR IS IT JUST AT THE STEERING ?? GET BACK TO ME IF YOU WANT TO ON MORE INFO ON THE VIBRATION. GOOD LUCK, ,TOM