Reduced engine power

I was driving my truck back home (70mph) and dashboard said reduced engine power so it slowed me down to 50 then 40 pulled to the side turn it off disconnect battery connected everything again turned work fine for at least 300 ft and turned off completely now it wont start…any ideas what could be ?..i switch the throttle body and is not it

Year? Make, Model?
Did Any “Check Engine” Message Appear?

I’d start by checking for DTCs (diagnostic trouble codes).


Sorry it is a 2005 chevrolet silverado

Nd yes it did

I’m sorry, but there’s way, way too little information here to even begin. This isn’t like taking it to a shop, where they can see the truck, the engine, the mileage, and begin to assess the problem. With internet forums, you have to give us all the details that a mechanic hands-on could see for himself.

For example,
what engine is it?
how many miles are on it?
do you have gas?
what does it do when you try to start it?

No offense intended, but I think you should just have it towed to a reputable independent shop and let them look at it. You’re going to end up at a shop anyway, so you might as well just “bite the bullet”.

Does it have fuel pressure (measured at the rail) ?? Does it have spark??

2005 silverado 150xxx
6.0 with a cam 238/240 605/609 112 lsa
When i try to turn it on it would just want to start but dont turn on dashboard says reduced engine power and engine light is on. Google said could be throttle body i switched it out and made no difference.

When the “Reduced Engine Power” is displayed, it usually means the computer has detected that an overheating condition is about to occur. This could be caused by the engine running too hot or the transmission is running too hot.

The computer reduces the engine power to prevent the overheating from occurring and so you’re able to limp the vehicle to a place to be serviced/repaired.

When this occurs a code reader won’t be of much use. You need a factory type scanner to diagnose the problem.


When it is turnd off no fuel comes out but just a bit at the rail and yes it does spark

If My Memory (What Memory?) Serves Me, I Have Had “Reduced Engine Power” Messages For Things Other Than Imminent Overheating.

Two that come to mind are a faulty transmission speed sensor and a false reading from an accelerator pedal sensor.

However, I have not experienced the vehicle shutting down and failing to restart. In both instance my code reader code give me useful information.
Could something like a crank sensor fault cause this?


When you replaced the throttle body, did it included the TPS? Also, could be the the wiring/connector to the TPS. Be sure to watch part 2. It has the cheap fix.

Ok guys so i found out something is blocking electricity to turn my fuel pump on i tried direct and it turned the fuel pump on but truck still cant turn on…i check the iif gas was flowing through rail to fuel injectors and it was…but truck still cant turn on…it is not the throttle body nor the sensor neither the pedal sensor …knock sensors seem fine anf ground wires on the back of the heads are grounded correctly …mass air flow sensor its clean and active…any suggestions on what could be other than “take it to a shop”