[mechguy78]

I noticed this on my way home from work last night. I was in fourth gear accelerating and when the tach hit 3k the turbo started surging with the throttle held steady. It didn't stop until I let off the throttle. Played around with it the rest of the trip home and every time I hit 3k the turbo would surge.I do have a p0420 code that will be getting looked at tomorrow, is this related? Has anyone else experienced this?

 

[yt400pmd]

i have this issue as well. i feel mine surging in 2nd gear, 3k it surges about 3.5k it feels like normal then at 4k it surges again
i do not have any codes

 

[jblackburn]

Usually how these engine management systems deal with knock - build boost, dump it off, try again.

What grade fuel are you using? If it's 87, go up a grade or two.

 

[ChevyGuy]

What grade fuel are you using? If it's 87, go up a grade or two.

At least until the weather gets back to normal. The hotter it gets outside, the worse the problem.

 

[mechguy78]

Have always ran 93 in the car. I did notice that it's not doing it today with the rain. There was a pending p0325 that was there a few days ago, but that disappeared on its own by the time I got to the dealer for my cel. I'll keep an eye on it when it warms back up

 

[jblackburn]

Have always ran 93 in the car. I did notice that it's not doing it today with the rain. There was a pending p0325 that was there a few days ago, but that disappeared on its own by the time I got to the dealer for my cel. I'll keep an eye on it when it warms back up

A knock sensor acting up could definitely cause that kind of behavior

 

[mechguy78]

Dealer cleared the light and told me to come back in if it comes back on as they were to busy the day I went in to look at it. Since driving more normal, no light or issues. I may have to try another 800+ mile tank and see what it does as this all happened in the last 100 miles of my 817 tank. I'm wondering if these were from driving overly efficient, like beyond the scope of what the car or computer were designed to do.

 

[obermd]

Dealer cleared the light and told me to come back in if it comes back on as they were to busy the day I went in to look at it. Since driving more normal, no light or issues. I may have to try another 800+ mile tank and see what it does as this all happened in the last 100 miles of my 817 tank. I'm wondering if these were from driving overly efficient, like beyond the scope of what the car or computer were designed to do.

Since water and gasoline don't mix well I wonder if you didn't have some water in your tank and the car was having problems handling the water.