MAF sensor brand

[OR VietVet]

Replaced maf sensor.

Turned on escalade and the ltft started reading 7-9% and iat sensor was normal. Way better improvement. Took it for a spin and car feels lighter at take off. But ltft are still not at zero. Then i realized that i did not reset the pcm. I will disconnect negative cable tomorrow before starting for about 15 mins and then ill see what changes.

Yep, cleaning is not a guarantee. I hope the replacement does the trick.

 

[Doubeleive]

I would check those cat's also especially with that low of a mpg

 

[Fless]

Since the fuel trims were so positive it may take a while to burn all of that extra fuel out of the system. Also might be a good time to change oil if it has gas in it.

 

[crownvic31]

Ok so this morning before going to work i went ahead and unpluged the maf sensor and negative cable from battery. Let it sit for 15 mins and hooked everything back. Everything was ok on my way to work(15mins). On my way back home, everything was back to before. 7.6 mpg on dash and ltft at 15-18 both banks 1 and 2.

How do i go about testing the cats?

 

[Doubeleive]

Ok so this morning before going to work i went ahead and unpluged the maf sensor and negative cable from battery. Let it sit for 15 mins and hooked everything back. Everything was ok on my way to work(15mins). On my way back home, everything was back to before. 7.6 mpg on dash and ltft at 15-18 both banks 1 and 2.

How do i go about testing the cats?

one way is the measure the temps with a infra red thermometer harbor freight has some not-too-janky ones for about $30, if you have a good enough diagnostic tool you can monitor them from the live data feed. and another way is to do a backpressure test where the 02 sensor screws in.
right about the time I started checking mine because I was getting about the same 7.5/8mpg one of them decided to throw a code for inefficiency, replaced them both and mpg went back to normal, that doesn't mean go out and replace yours, check them of have them checked to rule them in or out or just keep driving it and if one or both are bad it will throw a code eventually. or it could be something else but one of the signs is a drop in mpg

 

[Fless]

Is your scanner indicating that the fuel control system is going into closed loop?

 

[crownvic31]

Yes, it is going to closed loop. I have an Autel MK808. It does some live data. City driving went down to 6.9-6.7. Went on the highway and went up to 8.6. When at highway speeds i lift my foot of the pedal and then slightly accelerate and the car feels very sluggish unless i push the pedal. I will go out and buy the
infra red thermometer

 

[crownvic31]

Quick update

After performing several smoke test and having no visible smoke, i started hearing some what of a hissing sound. I then noticed a wet spot on the block where the engine dipstick tube meets and notice little bubbles of oil sipping out due to the pressure of the smoke test.

This might be a possible cause to my issue. What you guys think?

 

[Doubeleive]

Quick update

After performing several smoke test and having no visible smoke, i started hearing some what of a hissing sound. I then noticed a wet spot on the block where the engine dipstick tube meets and notice little bubbles of oil sipping out due to the pressure of the smoke test.

This might be a possible cause to my issue. What you guys think?

smoke test for what?

 

[crownvic31]

Another thing i want to share is that while my stft mv were switching just super great, my ltft would sometimes drop down to as low as 151mv and freeze and then bounce back to 851mv and freeze and so on. I thought ltft had a steady range of 700mv or so?

The ltft mv are all over the map while driving.