I have an 06 cobalt and recently my car started to suddenly lose power while driving. It says reduce engine power when this happens. If I turn the car off for a minute it'll go away.

Still sounds like 'limb mode' to me, but that should trigger some engine-warning light on the dashboard (and definitely internal error codes). The dashboard-light could be broken ofcourse. Would suggest taking it to a dealer for OBD-diagnostics (i.e. reading the internal error codes), that should be a good start.

Guessing what it could be: (MAF, O2) sensors, injectors, overheating (fan not spinning up when need ?), bad fuel, throttle-body, old fluids / oil, clogged fuel / air filters ...

it's recalled, what , you dont watch TV?, (id dont either) but do read WSJ.com
and GM has recalled massive cars. for bad ignition switch.
(using insane heavy key chains is true cause, not GM, IMO)

get it fixed for free, heck even other thinks related for free, as they dont
want any lawsuits. related to ENGINE DIES> and AIR BAGS DIES>
go get em.

sounds like the camshaft sensor or the crankshaft sensor, either way I think your car is being recalled for a faulty ignition switch which could turn off by itself.

Check the fluid level in the transmission as the level may be low after it filled the cooler in the radiator. Run fault codes and check for faulty TCM

As far as the cobalt, check tac/throttle actuator control. Below is circuit description for p1682.
The other codes was for knock sensor.

Fuel Sys, Driveability, Filters (Air & Fuel)
2006 CHEVROLET COBALT

02/01/2006 ELIMINATION OF FUEL FILLER TUBE FLAPPER DOOR 03/01/2006 ERRATIC FUEL GAUGE READINGS 06/01/2006 USAGE OF E85 FUELS IN GM VEHICLES - REVISED 06/01/2006 L61 ENGINE MALFUNCTION INDICATOR LAMP (MIL)/SERVICE ENGINE SOON (SES) LAMP ILLUMINATED WITH DTC P0171 "FUEL TRIM SYSTEM LEAN" SET 07/01/2006 TOP TIER DETERGENT GASOLINE - DEPOSITS, FUEL ECONOMY, NO START, POWER, PERFORMANCE, STALL CONCERNS - REVISED 07/01/2006 USE OF E85 FUELS IN VEHICLES NOT CERTIFIED BY GM AS BEING FLEX FUEL COMPATIBLE / AFTERMARKET CONVERSIONS OF VEHICLES TO OPERATE ON E85 FUELS 09/01/2006 397.pdf&btitle=2006 CHEVROLET COBALT&yr=2006">GM FUEL SYSTEM TREATMENT PLUS, FUEL SENDING UNIT CORROSION AND FUEL SYSTEM DEPOSITS - REVISED 11/01/2006 940.pdf&btitle=2006 CHEVROLET COBALT&yr=2006">ERRATIC FUEL GAUGE READINGS - REVISED 03/01/2006 USAGE OF E85 FUELS IN GM VEHICLES - REVISED 12/01/2006 TOP TIER DETERGENT GASOLINE - DEPOSITS, FUEL ECONOMY, NO START, POWER, PERFORMANCE, STALL CONCERNS - REVISED 01/01/2007 EMISSION RECALL - ENGINE FUEL INJECTORS - REPLACE 01/01/2007 LSJ, L61, LK5, L52, LL8 ENGINE - REDUCED ENGINE POWER, MIL/SES LIGHT, DTC P1516, P2135, P2138 02/01/2007 MULTIPLE DRIVEABILITY SYMPTOMS DUE TO CLOGGED FUEL INJECTORS, MIL/SES DTCS P0171, P0172, P0174, P0300, P1174, P1175 - REVISED 03/01/2007 MULTIPLE DRIVEABILITY SYMPTOMS DUE TO CLOGGED FUEL INJECTORS, MIL/SES DTCS P0171, P0172, P0174, P0300, P1174, P1175 - REVISED 05/01/2007 MULTIPLE DRIVEABILITY SYMPTOMS DUE TO CLOGGED FUEL INJECTORS, MIL/SES DTCS P0171, P0172, P0174, P0300, P1174, P1175 - REVISED 06/01/2007 <A href="http://arrc.epnet.com/autoasp/data.asp?sid=122357497&uid=s9193090.remote.autorefctr&type=pdf&ff=082000

Check the drive belt,and the alternator,most likely if the belt is still on,and it is running on the pulleys ok,then the alternator maybe out,have it checked,with out the alternator working the engine will not perform.

That is a hard problem to pin point without knowing what codes the computer has stored. It can be any number or sensors or engine problems.

You can go to most auto parts stores and they will pull the codes for you for free.

The computer has detected a fault in the emissions system that could damage the engine. It disables the engine so you cannot drive it and damage it. It must go to the shop. This sometimes happens after an aftermarket exhaust system is installed and it was not done properly or if engine modifications were done improperly. This can clog the catalytic converter and cause higher back pressure.

make sure your using the high grade gas, thie lower ones will cause damage to the engine, it's a small engine but a good one, so it is desingned for the higher grade to make the most of the fuel efficentcy.....shia....hope this helps