Misfires on one bank

[Potius]

The stft for both is around 0. The ltft around -18%. O2 sensors are new and genuine gm with all reading good voltages. As to oil I did just do a change about 600 miles ago. Not sure about tank pressure voltage but will hook up scanner when I’m home and check. The Fuel Cell Trim isn’t the ltft or stft but has its own pid on scanner. Not sure what it is tbh

 

[mikez71]

According to google, fuel cell trim is LTFT and STFT combined...
But as usual, the source they link mentions nothing about it!

Might check the fuel pressure and air filter too if you haven't already..
Make sure trims are fairly even bank to bank..

 

[Fless]

The stft for both is around 0. The ltft around -18%. O2 sensors are new and genuine gm with all reading good voltages. As to oil I did just do a change about 600 miles ago. Not sure about tank pressure voltage but will hook up scanner when I’m home and check. The Fuel Cell Trim isn’t the ltft or stft but has its own pid on scanner. Not sure what it is tbh

Do you mean "Fuel Trim Cell?"

 

[Potius]

Do you mean "Fuel Trim Cell?"

Yea sorry

 

[Potius]

Can’t see tank pressure voltage on scanner or anything similar. Steady felt misfires still on cylinder 4 and now 3 only at idle and no CEL. Got curious today and unplugged MAF and restarted the truck and there was no misfires at all. Could it be as simple as the MAF which I’ve been hesitant to change?

 

[Doubeleive]

Can’t see tank pressure voltage on scanner or anything similar. Steady felt misfires still on cylinder 4 and now 3 only at idle and no CEL. Got curious today and unplugged MAF and restarted the truck and there was no misfires at all. Could it be as simple as the MAF which I’ve been hesitant to change?

Could be a bad MAF, I have seen them cause a whole host of seemingly unrelated codes and problems, shifting problems, misfires, lean codes, 02 codes.
even though they "seem" unrelated bad maf data can cause the whole thing to go goofy.
my experience in general has been if it has 160k on the maf it's end of life and should be replaced.

 

[LsHart]

I sure that is a tall tell sign the MAF is bad if it runs better with it unplugged. ‍

 

[LsHart]

Don't go cheap either. Do ur research.

 

[Potius]

Yea I’ve given up hope of finding an oem one lol so I was thinking either Delphi or cardone. I usually like ngk but it looks different so not going with that

 

[LsHart]

Was thinking too, about one bank misfire. Coil pack housing ground or grounds?

 

[Fless]

Isn't the MAF also the Intake Air Temp Sensor? Has the IAT value been verified with a scanner?

What does the MAF report in grams/sec at hot idle? State the idle speed, too, or show it on the scanner along with the MAF reading.

 

[Potius]

What led me to unplugging the maf was the scanner reading. At idle it was .01 and at 3k rpms it only got to .02 I believe it’s in lbs/min

 

[Doubeleive]

What led me to unplugging the maf was the scanner reading. At idle it was .01 and at 3k rpms it only got to .02 I believe it’s in lbs/min

delphi if those are your choices, delphi is what might be in the oem box anyway

 

[LsHart]

If I remember, Delphi is what you want.