I have a 1996 Chevy Blazer 4x4 4.3L V6 with 135,000 miles. It has had issues with losing power at highway speed for a few months, the only code I have gotten was for a lazy o2 sensor which I replaced and got nothing out of it. I have a done full tuneup on this thing and some more, and still am having the same issue with power loss. I left from Washington to drive up to Alaska, made it 25 miles and was going about 65 miles an hour in overdrive. Usually the truck slows down a bit going uphill, but no so much that it has to downshift..but this time it was like my truck just gave up on life and decided it didn't want to move anymore! I had the petal to the floor and could barely keep my speed to 45 miles an hour with her pinned. It felt like my brakes were grabbing but the dealer said they are working fine (even tho my pedal is squishy due to the owner before me not knowing how to do ABS brakes). I stopped, pulled over, waited about 5 minutes then turned around. Once I had stopped and headed back home it was driving close to normal again (odd). I stopped at a gas station to check all my fluids, to find that my transmission was just about bone dry. I two days prior I had jiffy lube service my tranny and look for leaks.. they found nothing...the last people to flush my transmission was them, and obviously they do not know the correct amount of fluid to put in there or something, because both times I have gotten it done by them the dipstick shows I am bonedry right after they work on it. IF my tranny is messed up from having low fluid lvl because JIFFY LUBE didn't put enough in...am I entitled legally to make them pay for any repairs needed? SO....while at the gas station I poured some fluid in my tranny, drove a little bit went through all my gears, then added more (1quart in total) and it seems to be running/ shifting a lot smoother. Could my transmission being really really low on fluid cause it to overheat, thus causing my vehicle to lose almost all its power? And wouldn't this give me a check engine light? I mean the truck's power is so weak sometimes I cannot seriously believe that a check engine light hasn't came on. Been almost 2000 miles still nothing but that o2 sensor a month back. And the dealer is lost as to what is going on... Please. I hate this Blazer, its just been a PITA since I had it. Any help or suggestions will help. I really need to get back up to Alaska, and do not want to drive this vehicle until I find out what is going on with it after what happened the first time I tried to leave within 25 miles. HELP! The dealer did a drive test with the computer hooked up to see what was wrong and they said they cannot get it to give any codes whatsoever. EVERYTHING passed their inspection and I have no clue what to do! Is it time to just trade it in and get something newer? I have put so much money into it already trying to figure what the hell is going on with it and I have just about had it. Pretty disappointed that I spent 100 dollars at the dealer for them to just tell me nothing is wrong with it, when there definitely is. After I told them I was driving through canada to alaska they said, well just try it out and wait for a check engine light to come on...how stupid do you think I am? Drive my broken truck to break it more and then come to you guys and fork more money over? LOL

1999 beetle. The compressor will not cycle unless the rpm is 21-2200. I've added one can of 134, when it does cycle it's good and cold so I don't think I should add more.. I'm thinking a bad pressure switch maybe..? Any thoughts? Thanks!