Reduced engine power

Facts and evidence:
1. Happened to be very low on fuel and not driven for 6 days. (Go figure!)
2. When started on the 6th day, it was as if the battery were DEAD, then it very slowly turned over and started.
3. The message "Reduced Engine Power" displayed and the vehicle would not go more than 5 mph. Parked it and retried several times with the same result.
4. Then it started hard but ran fine except for slow windows and reduced AC coldness and output.
5. Put gas in it but have had the same experience each day since.
6. After another episode today (day 8 since the initial problem presented) I was blessed that I wasn't stranded
7. Now the "Check Engine" light is displayed. (Sounds like a good idea but funds prevent that right now and we have 5 children and our other vehicle is a Camry)
8. The battery has obviously been asent since the clock resets now every time it starts.

8. On the side - in case it could be relevant - the speedometer sometimes malfunctions and Chevy has let us know they are aware.
The driver's seat suddenly decided to reverse the direction of the controls.
A lighter power source quit.

The engine goes to "reduced power" mode. May do it at any time, may do it once or twice per day or not at all for days at a time. No apparent reason such as low coolent or low oil level or whatever. Local GM dealer ran diagnostics according to their prodocals and concluded that the throttle body needed cleaning. They also test drove the vehicle and it appeard to be resolved. I drove about 50 miles and condition returned.
Any ideas?

The check engine/emissions light has come one and the dash display says "Reduced Engine Power". The vehicle is running at only 10 miles per hour and the rpms range from 1000 to 2000 without gas. I had taken it in to have the passanger side window motor checked a couple of weeks ago and they tried serveral ways to see if the motor was bad including direct power. So the motor is bad, but I noticed the next day that it would start right away, like the battery or alternator weren't powering properly. It has done that every time I start it. I have called the shop to let them know they did something scewy with my wiring, but would it be the cause of the reduced power and engine light coming on? Has this wrecked my battery?

It started out a couple weeks ago. The locks would cycle and simultaneously the car would loose power for a second, and all the dash lights would come on, and even the air condition coolness would turn off. If I turned the car off. Everything would be fine until it would do it again a minute or two later. Now there is a engine light on and it reads reduced engine power. And the car barely runs

I used the guide above to fix my problem thank you.

A DTC Code P1518 appeared on my '01 Chevy Suburban 2500 2WD 6.0L and at the same time a message saying "Reduced Engine Power". I had a machanic check the wiring and ground connections. The error returned after driving just 35 miles again. My TAC module has a part no. "BD 25173339 C" that I am trying to find used. Online suggests that a number of other vehicle models use the same module, how can I know if I have the correct module? Also I don't know the difference between refrences to TAC, ECM, or PCM modules. Can you help me please?

K1500 5.7 L Vortec Engine

Engine will start and runs fine when cold.
After1-2 miles driving engine, it will not come up to
speed. It backfires through the intake as if lean fuel air mixture, bogs down and no power. I've read about a "limp home mode" that seems to fit what the car goes into. I shut the engine off and it immediately restarts and everything fine for a few minutes and then it reverts back to same problem.
Fuel pump first replaced Dec 5-08 after showing signs of being noisy and engine not starting one day. This new pump became noisy after a couple of days and then lost power on December 25th. It was then replaced Dec 29th with a fuel pump with a different style with modified connector. There have been problems with the original fuel pumps. The fuel filter changed again, 60-65 psi fuel pressure at test port. Fuel pressure regulator, spark plugs, cap, rotor and cool sensor replaced. Intake manifold gaskets replaced. O2 sensors replaced at shop after their codes read needed replacing. The shop not able to diagnose, only that the intake manifold had a severe leak that was then leak fixed at our home. The shop scan codes read P0131 O2 low voltage P0151 O2 low voltage, P0405 EGR Sensor "A" Circuit low, P0102 Mass Air flow low input. The Mass Air Flow sensor was cleaned with "Sensor Kleen" before going into the shop. This nightmare has been going on for almost 2 months. The next step might be to replace the Powertrain Control Module (PCM), I have been reading that all too often technicians tend to blame that which they understand least and if the engine is not running right and the cause is not obvious they may blame the computer. No codes are showing from the hand held scanner we put on the car after taking it out for a test drive yesterday. My husband is retired and our funds are getting low for fixing this vehicle. We would appreciate any help you could give us.

Thank you for your response.
CAT (convertor) checked and not the problem.
During the test drives, everytime
the car will start right back up after
the ignition is turned off. It has lots of acceleration and power for another 2-3 min. And the same cycle again after turning the ignition off. Could you describe the "Limp home mode"? We are not sure if that is what is happening with the car, only that it sounds like what we have read about.
How can we tell if the Powertrain Control
Module is to blame? The scan tool shows no problem codes after test driving or anytime. Also, it shows no problem codes even when two or three engine sensors are disconnected. It will generate a code when the fuel cap is off while testing. Check engine light has never come on. I look forward to any light you can shed on this problem. Thank you.

Thanks for your reply. We had it into the shop on
Jan. 16th and they ran a scan. It showed
PO131 O2 Low Voltage, PO151 O2 Low Voltage,
PO405 EGR Sensor "A" Circuit Low, PO101 Mass Air Flow low Input. They replaced both O2 sensors and said they
couldn't diagnose any further until the intake manifold leak was fixed. My husband has fixed the leak and replaced the gasket but we are still having the same problems. So far over $900 in parts and $467 to the shop and we still have the same problem. I had it out for a test drive yesterday and was able todrive 3 miles at 40 miles/hr before it started to lose power. I parked it for 20 min. And then started it back up and lost power after driving a short distance. After it stalled I put it in neutral and started it back up, without turning off the ignition. This time it would only go a short distance before losing power. The next time I turned off the ignition and got further but only a mile at a time before having to shut it off. It seems that when the ignition is turned off, the computer reboots. Does this make sense? Would that indicate the PCM would need replacing? Thanks again for your help.

Car has run well for 8 years. A few weeks ago I was getting into traffic and stepped on the gas. The truck lost power and went into limp mode. I drove home at about 25 mph. Since then it has come on sporadically without provocation. I changed out the plugs, wires, distro cap and rotor. It ran great for a couple days. Then it did it again. I disconnected the timing lead to the computer and set the timing (it was retarded about -8 deg). Ran great. I plugged the lead back in, the computer took over and advance the timing to about +12 as expected. After a few minutes the computer lost interest and the timing returned to 0 deg. And the check eng light came back on. So why is the computer going into Limp Mode? P.S. The engine revs nicely in the driveway, so I don't think its the fuel pump or filter.