Untrained

The plugs have about 10k on them. I used throttle body cleaner, and sprayed every hose I could find. I have my own code reader, and that's how I found the O2S code.

BareBonesXL

If your code reader will do "live data" you'll be able to see the fuel trims while the engine is running. If they're high that's a sign of a vacuum leak. Most fairly modern control systems will adjust parameters super quick to hold a certain idle speed. So the old way of listening for engine speed changes while spraying hydrocarbons doesn't work well because the computer is too fast. But, with live data, you can see the computer make changes to fuel trim as you spray at the trouble spots. And some of the vacuum leaks are at the intake manifold gaskets.

I'm just suggesting a bit more diagnostic work, if you have the tools. Sounds like you might. It's pretty incredible how deep you can see in to the engine's computerized control system these days, with just a phone or a laptop.

Untrained

I actually do have a live data option on my reader, just most of it I'm not too familiar with. What would be considered high fuel trims? I believe it's in percentages correct? I could check this fairly easily, as my grandparents currently have the truck.

akdoggie

fuel trim readings

BareBonesXL

You can find a few very detailed threads on the forum if you search "fuel trims" and "live data". I think.

Here's a couple from Makuloco. Not your engine but the first shows typical leak spots, and the second goes in to detail about fuel trims and other things. Notice in the first video the screenshot, early on before he starts poking around, with the high percentages. If the sum of long and short trims isn't in the teens to 20 range you probably don't have a vacuum leak. Also, vacuum leaks tend to be worse at idle, so watching trims as you increase RPM will tell you something. And if it's a gasket problem they often get better as the engine warms up and the gaskets seal.

Anyway, you'll either watch the numbers and see something or it will be a bunch of gibberish. Worth a shot.

white89gt

AK comes through with another gem!

Untrained

I've just plugged my reader in and checked all of the fuel trims, and they show no signs of a vacuum leak. The short term trims at idle never went above 1.5%, and during normal driving, not flooring it, they never went above 10%. The long terms were about the same thing. What I just remembered though, is I forgot to also focus on the MAF readings. The reader I have is automatically set to g/s, and I can't set it to the voltage. Before I started the truck though, the air flow reading was at about 11 g/s. Wouldn't this indicate a bad MAF sensor? Looking back over the readings on my chart, the fuel trims do seem to spike up and down rapidly between 5% and -5%.

BareBonesXL

Makuloco has a video about how to tell if the MAF sensor is bad. It's out there somewhere on his channel.

Your trims look good though. At least you can stop looking for vacuum leaks.

akdoggie

I'm more interested in what your fuel numbers are, not what %age it changed. Can you post your low and high readings at idle warm? Then a 2k rpm high low reading?

Untrained

Just when I was giving up on myself, I was given a sign. The truck decided to throw a check engine light, finally. What I saw was the code to a Bank 1 Sensor 1 O2 sensor. I replaced the sensor, and after 5 hours of agony, the light is off and the truck runs beautifully. At the moment though, I am the only one that can sense a sliiight shake. From what I have heard though, these trucks do have some kind of a very slight rumble. I also just saw the suggestion to post the fuel readings, my bad.