[Time-to-fish]

Gf was traveling, come up to stop light and said vehicle seemed like it wanted to die at complete stop. Pulled the code and was getting a p0303. Only fault code. Replaced plugs and no change. For further investigation I unplugged coil pack for number 3 and symptoms got worse. For the most part in my mind that would tell me coil pack is not the issue. As of this point and time I am at a loss. Symptoms upon vehicle operation are rough idle, power loss and a very noticable decrease in fuel economy. Also symptoms happened suddenly as vehicle was running good less then 24 hours prior. Suggestions to help point me in the direction would be great!

 

[David B.]

What year and how many miles?

 

[AlisoBob]

I unplugged coil pack for number 3 and symptoms got worse.

This is what your called #3, correct?

 

[Time-to-fish]

What year and how many miles?

It's a 2010 and it has 110000

 

[Time-to-fish]

This is what your called #3, correct?
View attachment 8993

Yes that is number 3

 

[Time-to-fish]

I also just replaced coils today. Power seem to be a little better but still really rough idle. Had the battery disconnected as well as I replaced coil packs. Drove it around for a bit to see if it would throw code and it did not.

 

[AlisoBob]

With the intake off, did you look down the intake ports and see any nastiness?

 

[David B.]

Did you use A/C Delco plugs? These engines can be picky. If you used Delco plugs and replaced the coil, I would go with AlisoBob here and venture to say you may have carbon build up. Maybe run a couple of bottles of Techron concentrate plus through it?

 

[Time-to-fish]

With the intake off, did you look down the intake ports and see any nastiness?

View attachment 8994

Yes i did and they did not look nearly that bad. Also I noticed it used a 1/8 tank of fuel and only drove about 10 miles. Like I said the symptoms come on very sudden.

 

[Time-to-fish]

Did you use A/C Delco plugs? These engines can be picky. If you used Delco plugs and replaced the coil, I would go with AlisoBob here and venture to say you may have carbon build up. Maybe run a couple of bottles of Techron concentrate plus through it?

Yes I used ac delcos.

 

[AlisoBob]

Also I noticed it used a 1/8 tank of fuel and only drove about 10 miles. Like I said the symptoms come on very sudden.

This is sounding more like a malfunctioning injector.

Sudden onset
Rough running
Plugs and Coil made little difference
Excessive fuel use.

All this points to the Cyl 3 direct injector

 

[Time-to-fish]

This is sounding more like a malfunctioning injector.

Sudden onset
Rough running
Plugs and Coil made little difference
Excessive fuel use.

All this points to the Cyl 3 direct injector

I actually just watched that video. And the more digging I do the more that seems to point to the injector. Got some running around to do and wel see if it throws light again.

 

[Time-to-fish]

Well went and picked up injector today and had them scan vehicle and it is now throwing a multitude of codes. 3 P0300, 2 p0301, 2 p0303 and a c0561.... this vehicle is becoming a nightmare.