Then its on to sensors:

What are the MAF readings in live data at idle and 2500 rpm?

Do the ECT readings agree between the dash and live data when the truck is warmed up?

What are the O2 sensors doing in live data?. Are they flopping up and down and what frequency and levels?

With the engine off do the TPS readings move logically in step with the movement of the throttle?

George

 

To the OP. You will need to plot them to see what O2 sensors are really doing - they generally cycle quite rapidly and displayed numeric values are only snapshots at any given time (not the full picture). Same way with STFTs. Helps to have a fast scanner and/or be monitoring just the pertinent PIDs. Sorry George, I couldn't resist adding that comment. Please carry on!

 

Les

No problem, I was assuming limited OP capability. As you suggest, live data graphs are best.

George

 

DB

If you have an Android device, Les can get you set up with a cost effective increase to your scanning capability.

George

 

George,
Well here is what I think are correct readings for your question,
TPS or on my reader it is TP reads 0.0 at engine off and on, and then moves up with pressure on throttle.

Mass Air 5.7 to 6.4 at idle
at 2500 RPM it is 18.5 to 22

TPS reads 194 and the dash gauge reads just under 210

The o2 sensors are hard to pin down as the readings are fast but here goes

bank 1
Level .1 to .800
Frequency on my reader is a % line and that is 0 to 1.6

bank 2
level reads .1 to .860
% .8 to 1.6

Thanks for any help.

DB

 

Sorry gents no smart phones or tablets. I am retired and my Macintosh and my cheap *** flip phone is all I need. But I am being seduced by the level of IPhones and Galazy phones they are sexy hot and do just about everything.
DB

 

I forgot to ask you what the IAT and ECT temps are on a cold engine to see if they agree which is another first order measure of if the ECT sensor is working correctly.

 

George,
Thanks for the help so far.
KOEO
Ambient temperature is 71 degrees
The IAT is 64.5 degrees
The ECT is 60.8

 

Nothing catastrophic in these numbers so that means that your problem is most likely something marginal and/or more than one issue which can take some work to pinpoint.

It looks like your MAF is under reporting, has it been cleaned or replaced? If not you may want to try cleaning it with MAF cleaner spray.

What is the history of the O2 sensors because they look like they are operating but if they are sluggish this will increase fuel consumption.

Have you looked at any of the plugs for evidence that the truck is running rich?

If you remove the air intake at the throttle body and open the plate, does it smell like gas (leaking injectors or regulator)

Do you have an EGR valve and if so has it been cleaned?

Do you have any reason to suspect any compression problems? A first order check is to defeat the ignition and crank the truck for say 5 seconds and see if the cadence is off.

If you look at live misfires, what does it look like?

What do your rpms look like at speed (transmission slipping)?

George