The gas mileage was due to the numerous broken issues, Oxygen sensor and MAF sensor. But, it has almost ALWAYS been that bad, even considering 80% of my driving is highway.
I also forgot to add, the throttle body will gum up and need to be cleaned. Evidently this is another one of those common place perks to owning a Trailblazer; the throttle body has to be cleaned fairly regularly. I say fairly regularly, because I've never heard of anyone having to clean a throttle body more than once.
Oh, and the rear differential popped. Fluids need to be maintained and flushed.
But yes, first and last Trailblazer, and most likely my last mid-size SUV, considering everything is a crossover below full size now; I don't see the point in just owning an SUV that isn't anything more than a car, with an SUV body.
Oh yeah, we had that throttle body cleaning issue as well. Ours was stalling spontaneously, which became very dangerous when you were taking off at a light. It was very hard to start after it stalled, but eventually it sputtered to life slowly. It also idled very poorly. I remember it was very difficult to back up to the boat trailer with it, as it would suddenly surge after acting like it was going to quit. I was thoroughly fed up with that vehicle overall.
Most of the research I was looking at for this problem pointed to the computer module, but I did find that cleaning the throttle body was a possible remedy as well. We did that. It ran better for a short time, but then started hesitating again. It simply never ran that great after 50K miles. There were always issues with it. I am very glad to have traded out of that truck now. We have been trouble free for over a year and a half now, and hopefully I will never go down that path again of such ridiculous costly repairs on such a young vehicle.
We went with a smaller SUV ourselves, as we wanted to improve on the mileage. 24 mpg was great, but now we are up towards 30 on trips with almost 270 HP.
I have just over 190,000 miles on my LS. I bought it used with just over 50,000 miles. The dealer reluctantly replaced one strut just after purchase, because the car was handling funny.
Since then I have replaced the spark plugs twice myself, an O2 sensor and the brakes once. I replace the fan clutch, but it continues to hint at going out again. It's a pretty expensive repair. I think the part is nearly $200 alone. I took it in, because unless you have a well equipped garage at home, you'll need a few special tools. Also, the thermostat had to be replaced. That is a true pain in the A** to do yourself. I didn't know that until I was knee deep into the repair. By the time it was done, I was ready to put a bullet in this truck, but ever since, all has been forgiven. I recently (180,000) had the ball joints replaced :( But I do go offroad (trails) fairly often shooting/hiking.
One parting thing to remember, is fluids need to be changed. Transmission, rear end, oil, radiators, etc. When I hear trannys going out and slipping, just spend a few hundred dollars to save thousands later on either repairs or a new vehicle. Many things can be done at home with normal hand tools, and you get to know your vehicle better.