When the reduced engine power light comes on a fault code will be set in the powertrain control module. Reading the code and following the releated diagnostic information should help lead to the cause of your reduced engine power light coming on.
I just spent $200.00 for a new alternator...after no relief I remembered My ski doo..when the rider plug was in the half connected position it sputtered and would not rev up....Look on floor..go to the gas pedal...wiggle the wire bundle at the plug and try the engine. I did this and it cleared it up instantly.....expensive lesson to learn.....
Poor connections at the gas pedal or the throttle body are always a possibility when diagnosing "reduced engine power faults". If the connectors are loose or damaged and cannot be properly secured or the wiring is damaged then appropriate repairs should be completed to avoid reoccurring problems.
I have had this happen twice with my 04 Trailblazer, once last winter and again today. Both times it was at least 20 below zero so it definitely has something to do with the temperature. Both times I let my vehicle run for a bit and then I shut it off and started it again. It works fine after that. After the first time I took it to a dealer and they couldn't find anything wrong with it.
I have a 2003 Trailblazer LTZ with approximately 176k miles on it. Never really had any major problems but over the last year and half issues with the reduced engine power light and service engine light has plagued me. Having to pull over and restart my car and reset so that I could drive again normally. I went on several Chevy blogs to see what could be going on with the car. As you might guess I found out that I was not the only one experiencing this issue. So I started with what the on-board computer code was indicating a problem with the "Electronic Fuel Throttle", I removed it from my Trailblazer and cleaned it the best I could (I am no mechanic) and reinstalled (no help). Then I replaced the fuel filter and air filter, still no help even thought I'm sure it helped performance some. I then took it to a real mechanic and he drove the car and said I needed to replace "Fuel Throttle" at a cost of just over $700.00. That's when I found the reviews on Amazon of others with a similar problem and replacing their accelerator pedal with sensor in it. I ordered the part based on the reviews of this pedal. I received it as promised and installation was a breeze. Problem solved no more reduced engine power and service engine light so far and loved the fact I saved money the was not unnecessarily spent. I hope this posting will help others out there with this issue.