In need of a little assistance.

[Dm23]

What’s up guys.

So I have noticed my truck has been acting a little funky. For what ever reason when I go to floor it the truck just doesn’t want to. Very laggy especially at higher speeds 40-50. The Boost seems to come up no problem, it’s very hard to explain. Only thing I have recently done to the truck is the transmission fluid change. I thought I might have filled it to much, so I drained some out. Still same issue. I thought it might be the fass going out. Change the filters, same problem. Unplugged the fass relay, same problem. It seems like this problem has been intermittent. Once in awhile the truck will put me back into the seat and other times I’m waiting for it to do that and nothing.

There’s no smoke of any kind, no lights or dtc’s. I checked balance rates, actual vs desired, vane position,etc with my CTS3. Even logged the drive with about 16 parameters. Not sure how to post it here, so someone smarter than me could possibly take a look at it. I know it’s hard to try and diagnose over the internet. But any help would be great

Thanks in advance

 

[Woody35]

MAF Sensor?

 

[2004LB7]

The two items I find most often for lack of power when it's obviously not in limp mode is lack of air or fuel. Air could be MAF and check fuel pressure vs actual

Log both of those and report

 

[Dm23]

I will log the maf and see what happens. Thanks

 

[Dm23]

am I missing anything?

 

[Woody35]

Is boost pressure in KPa?

In your 5th picture it looks like you have a pretty good load on the engine and you are only reading 98 g/s from the MAF. That is way low.
What’s your air filter look like? Is your EGR Valve still intact?

 

[Dm23]

Honestly I’m not sure if it’s kpa. I will have to look in the morning. Air filter seems like it’s still good. Wc fab brand. I’ll post a photo of the air filter tomorrow as well.
No EGR, etc.

 

[Ron Nielson]

Maf is very low as previously posted. should be about 40 gm /sec at a warm idle in park. If yours is 17 GM /SEC at idle, start by cleaning it. That signal would lead to serious under-fuelling of the engine.

 

[PureHybrid]

I agree, MAF is terrible. 35-40 g/s idle, 500+ WOT

 

[Chevy1925]

If cleaning dont fix it, get a GM maf, nothing aftermarket

 

[Dm23]

Might need to order a new maf lol

 

[Dm23]

Here is what I logged

First photo was with the truck warm in park at an idle.

 

[Dm23]

And these were with the truck warm. From a stop to a drive/pull

 

[2004LB7]

As others have said. MAF value is way too low

 

[Bdsankey]

Has anyone said MAF yet? Like James stated, only genuine GM nothing aftermarket.

 

[Dm23]

I don’t think so lol. I ordered one. Along with a new wc air filter. Hopefully both will be here this week.

 

[Woody35]

They do seem to fail sometimes. I bought my turbo kit used and it came with a MAF sensor. A few months later I started the truck in the morning and a code popped up for it. Replaced it with my original MAF Sensor and its been running great since.

 

[Dm23]

It’s like you guys know what you’re talking about . Changed out the maf sensor and put on a new filter. Back to normal. Thank you guys. I really appreciate it