Reduced engine power light on

TWISITED SOUL

MEMBER
2003 CHEVROLET TRAILBLAZER
4.2L
V6
4WD
AUTOMATIC
206,000 MILES

My vehicle will not go over 15 MPH using a lot of gas. Yes, the reduced engine power light came on also I don't have any codes on it. My husband changed the throttle body and plugs. My sister has an Envoy she said hers done the same thing, and it ended up being one of the coil packs.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This could be a coil issue, so we need to start by checking the codes and finding out what is there so that we are not guessing.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

So, if we are going to see if this is a coil then we need to check for spark.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

Basically, we need to start with codes because there are a number of things that can cause this.

However, if the coil checks out then we need to check fuel pressure and I am sure by then we will have a better idea what direction to go.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/reduced-power-limp-mode

Let's start with this info and go from there.

Thanks