I have a 2008 Chevy Impala LT 3500 V6 with 133422 miles on it. It seems no not get off the line ir climb hills like I once did. Driving down the highway it seems to work fine, downshifting to pass other cars and is not running at higher than expected RPM. It also downshifts to climb hills properly at higher speeds 40 mph+ but other times is seems to have no power. If I park on a hill facing up it and put the car in drive and press the excelerator to the floor it goes from idle ~600 rpm to ~900 rpm and does not move an inch. The exactcsame thing happens trying to back up a hill. If I approach the same hill even at 5 mph the car will slowly climb the hill and may even gain a small amount of speed. I believe there are a few related issues to the problem if I drive the car to work ~ 35 miles on the highway, as soon as I get to stop lights and have to wait on Red the steering wheel has a shake/vibration. Then in the afternoon as I head home it develops further issues where shifting into Rev or Drive from any other location there is an audible squeak (sounds like a loose belt for a second) when it gets really warmed up and tired it starts to sound like an older diesel engine or a bad harmonic balancer while sitting with my foot on the brake in gear. Once it is in park it idles fine no shaking and no noise. I have a video that should show most of these issues. Thank you Nicholas
Well it seems to me that you have more than one problem. But not going up hills as often. The sign a clogged fuel filter or a weak fuel pump. Change the filter first and if that's not it pressure test the pump to see if it's bad. You can't just pressure test at first cuz if the filters clogged that'll give you a low pressure and it might just be the filter and not the expense of pump. That's where I'd start if you don't have any codes. But if you have any codes when it's scanned, you have to fix that first. The computer doesn't know what the fuel pressure is so if there is no code it's off in the fuel
Sorry forgot to mention there are no codes when scanned.