i too have also had a shall i say finiky time with my tunes, after i installed my LTs and refalshed my new 91 race tune with the back 02's shut off it felt more slow as i wrote about in a post a couple weeks back. i then uploaded the 87 tune for the LT's but i got a cel about the rear 02's not working or something, i forget, but it showed that they didn't shut them off in that tune.... so ran that tank empty and refilled and reflashed the 91 race at a gas station, first upload went bonkers with the "limp mode" showing up on the display and the car wouldn't even fire, just rrrrrrr, rrrrrrr, rrrrrr,rrrrrr. so i tried uploading it a second time, then it took. that was 2 weeks ago. last sunday i started my car and let it warm up and when i got back in, it had the cel on. shut it down, grabbed my sct and ran the codes, rich in bank 1 & 2, i thought ok - race tune - long idol- makes sense. cleared those and was on my way. next day bam!(a) :hihi: new cel, figured it was the same codes but it was a different one for low input circut on 02 for bank 2. cleared it but i still am sure that my old 91 race tune before the LT's was better, i think i might load that one and beat her around, i know i will get the cel but i want to see if the power thing was all in my head or what.