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While you're waiting for your tool, another thing you can do is take a look (and CAREFULLY clean) the little resistors in your MAF. Check the little wires connecting them to the metal bars to insure they aren't broken. I use a 10x loop to inspect them, but a magnifying glass (or 20 year old eyes ) will work fine. Dust and dirt can get baked on them and it can give incorrect data which can give you cold weather drivability problems. If the resistors are dirty, they will look crusty. It's a very simple thing to do while you wait.
I also wonder about fuel issue as George mentioned. As if it maybe it isn't priming correctly. Maybe prime twice before starting next cold morning?
I am curious if your fuel trim will be rich or lean when you get your tool. That will help with a direction.
Your fuel trims are way out of bounds. The O2 sensors are telling the computer to add a lot of fuel to attempt to compensate for a perceived lean condition and get the air/fuel mix right. In addition the engine computer does not like the way at least one of the O2 sensors is switching.
Was this data before or after you turn the truck off and restart it to get it to run right?
Run this data again at idle and 2500 rpm in park, engine warm
In the morning when the engine is cold run this data with just key on engine not running and make note of the ambient temp and barometric pressure
Can you graph the O2 sensors so we can see how they are switching?
Your Intake Air Temp (IAT) seems awfully high. I realize you were not moving but that strikes me as still way too high. The VCM uses the IAT to adjust fuel delivery and spark timing. Where do you live and what was the temp outside when you read this data? Honestly, I would look at testing the IAT and replacing, if necessary, as my first thing.
If the IAT is bad it will throw other things out of whack. Garbage in, garbage out.
Your Intake Air Temp (IAT) seems awfully high. I realize you were not moving but that strikes me as still way too high. The VCM uses the IAT to adjust fuel delivery and spark timing. Where do you live and what was the temp outside when you read this data? Honestly, I would look at testing the IAT and replacing, if necessary, as my first thing.
I was thinking the same thing about the IAT, seemed really high. I live in central Arkansas and the ambient temperature was 51° Farenheit. I went ahead and ordered an AC Delco IAT, it'll be here Sunday (hopefully). It's also one of the few sensors I haven't replaced yet.
In the meantime, test the one you have and the circuit. Just in case your problem lies in the circuit and popping the new one doesn't change anything and it was an issue in the wiring, etc. I'll post some images of a DTC P0112 (Sensor Low Voltage) testing out of my '98 shop manual when I get a chance. Besides possible wire color or cicuit# differences, test should be the same I would think.
EDIT: Didn't see your last post before I posted. Do you need testing procedures, or are you GTG?
12-13-2022, 04:25 PM
) will work fine. Dust and dirt can get baked on them and it can give incorrect data which can give you cold weather drivability problems. If the resistors are dirty, they will look crusty. It's a very simple thing to do while you wait.
