I have reduced power engine light on my 2002 avalanche

SOURCE: 2004 Chevy Tahoe - Reduced engine power message

have autzone check for any stored trouble codes, replace the fuel cap, make sure you have plenty of gas

SOURCE: 2002 reduced engine power light

You have some kind of ECU problem. You will need to hook to the diagnostic port to find the problem. Your vehicle has gone into limp mode. This enables the vehicle to run, but at a diminished level until you can seek help for the problem. Do not continue to drive it this way as you may cause damage to the engine depending on the nature of the problem.

SOURCE: 2002 Avalanche gas gauge problems

Gm has a real problem with fuel tank sending units. That is what is wrong. You need a fuel tank sending unit. You can only get them aftermarket with the whole fuel pump module, but you can buy them seperate if you buy it from the dealer.

SOURCE: 2004 chevy silverado

The above descriptions of the connector are very good. I washed the engine compartment yesterday, and immediately started getting the reduced enginer power code on the CIC, not performance. After reading several posts, I checked the connector on my 2003 2500HD, and found that the connector was not seated well and had gotten water in it. I cleared the water and the reconnected. The cables running from the fuse box to the connector are so short, the connector is in a bind and is pulled off-center. That is why the connector wasn't seated properly. The code went away, and the performance returned. By the way, be sure to do this after pulling the negative cable on your battery.

SOURCE: Reducded Engine Power

check the wires leading to you throttle body. i had the same problem and found a broken wire on the throttle body wiring harness. i repaired the break, had the computer reset and problem was fixed. hope this helps.