Nice! The graphs are really handy for watching o2 sensors and makes it much easier to see dropouts or spikes in sensor readings. A lot of the time, with regular number displays, the scan tool doesn't update fast enough and you'll miss things like that. I can only graph one thing at a time on mine, but with only one data pid displayed, the scan data is much faster.

 

Ok. Forgot to mention it before, but I was out tinkering on it today and remembered that if I quickly and repeatedly pump the gas pedal, it will rev up eventually all the way to 4500 or so, and if I keep pumping it, it seems like it would hold there. Probably doesn't help at all, but I thought I'd mention it. Scanner should be here on Mon.

 

Sanner came today. Ran the scanner, and collected the live data. Trying to figure out how to get it on the comp, so I can post it. I have no idea what parameters are acceptable for the different sensors. Or if I could figure out how to use the graph thing, and posting the graphs.

 

So, I am not sure I can get the data from the scanner to my comp, and I can't figure out the graph thing... So I will try to make this as non-confusing as possible... I took 25 frames of live data. I started with the throttle at 0, Intake air was reading at 90 (accurate), MAF read 1.95 lb./m. Noteworthy, was the Calculated engine load, which two values are listed, at an Idle one is 7.8%, and the other is 38.4%... I don't have any clue what that means, but seems off to me instinctually. RPM was 753 (for both values), and coolant temp read 90 also before I started it up. Ignition timing advance is 16 deg (not a clue here either.) I then gave it a smidgen of throttle. TPS read 4.3, and 5.1 (two values listed for most things. not sure why.). RPM is 1301, and 1315. Intake air still at 90. Calc load 7.8%, and 23.1%. Coolant is 163. Ign adv 30 deg. MAF 1.97 lb/m. I held it for a few frames, and see little change in values, but the fuel sys 1 & 2 say open2 in the next few frames, and short term fuel trim bank one and two drop to 0.0% (as opposed to the 25% previously up to this point.) I let it idle for a few frames, so it would smooth out again. Then I floored it, and held it for a few frames choking, and backfiring. TPS read 78.0% and 94.9%. calc load 7.8% and 39.6%. Coolant 180. RPM 690 and 703. Intake air 90. Ign adv 17.5 deg. MAF 1.99 lb./m.
Hope I don't sound like a nut job, and that makes some sense. On second thought, I could have just typed out each frame as a separate posting, and it probably would have explained it self. I will do that if this just confuses people... Sorry.

 

The two separate readings may be desired and actual. I'm not sure about that though.
I don't have any experience with this particular scan tool, but on mine I have to scroll down to the data pid I want to graph and press the enter button. Then it opens up just that data pid by itself in graph mode.

 

To me, those MAF readings don't look good at all. Have you tried cleaning it? If you've never cleaned one, it's not that hard. Spray a little bit of carb, or brake cleaner, or MAF sensor cleaner on a Q-tip. Then gently wipe off any buildup off the hot wires.
I think the can of MAF cleaner tells you to spray it directly into the MAF. I never do it that way because it doesn't clean them very well and you have to wait forever for it to dry.
One thing that causes major problems with MAF sensors is K&N filters. The oil gets on the hot wires and causes all sorts of drivability problems. If you have one of those installed, I would get rid of it and get a regular filter. MAF's get dirty over time, but those filters really speed up the process!

 

I did clean the MAF, with a Q-tip and MAF cleaner. soaked it and let it dry overnight and re-installed it. it didn't improve it, and it was acting differently than the last time it went out, so I abandoned my first instinct... What should the readings be? So it is likely my MAF again? No K&N here.

 

I don't know exactly what the MAF readings should be for this particular engine.
What are the long term fuel trim readings? That will tell you if it's running rich or lean.
The short term fuel trims are more of an instant reaction. The long term fuel trims are trying to pull the short term readings to zero.
Were the short term fuel trims at +25% before revving the engine?

 

long term fuel trim on both banks were -25%. short term fuel trim bank 1 -14.1%, and bank 2 -25.0%. I have two other readings labeled Fuel trim Bank/Sensor, it says
ST FTRM11(%) -8.6
ST FTRM21(%) -25.0

 

I'll try and see what my MAF sensor readings are at idle for comparison's sake. Some known good values to compare to from a properly running truck would be ideal here. Calculated load value seems low for WOT readings. Often times that points to a MAF issue.