Check Engine Light
 

The past couple of mornings, I've started the truck (stays parked in the driveway), and the check engine light will pop up after about 10 seconds of starting and running, but then goes out after about a minute.

I attached my SCT tuner to the OBD-II port (it also reads DTC's), it scans, but then reports there are no DTC's. I'm guessing my alternative would be to start the truck, as soon as the check engine light comes on, turn off the truck, then attach the tuner, and then just turn the key to on so that it can detect the code.

As stated, the code clears within about a minute after start. It just started doing this, and the only other thing I can possibly relate it to is that the past couple of weeks have had Florida with some cooler morning temps.

Going to AutoZone or Advanced, they might be able to see a code as "history" with their scanners

Could be a loose connector on control device or sensor
Computer does self check with key ON, so CEL comes on and then goes off, after that it does a control and sensor check, if one doesn't have correct response it will turn on the CEL and retest, if it gets correct response after that CEL will go off, and no code would be stored.

MAF/IAT, TPS, ECT, CPS are sensors wires I would check
IAC Valve is a control I would check.

O2 sensors are not used at startup but they do have a heating circuit that is tested, and it is higher amp circuit so could corrode easier.

Just unplug connector and give a look inside

I unplugged each of the mentioned sensors; they all looked good and clean. It was warm in the mornings tha past few days, so no CEL on first startup. Then we had a blast of cold mornings; in the low 40's, and the CEL lights up on initial startup, then clears itself after about 1 to 2 minutes.

I'm going to try and "catch" this code by starting the truck on the next cold snap we get, shut the truck off as soon as it lights up, then attach the OBDII reader to see what it is.

Next cold morning try turning key on, count to 3 then turn it off, turn it on again and start engine.
So prime fuel pressure twice before starting, 3 if you want, you can't over prime it.

Thinking is that your fuel pressure is low on cold start, the colder the air the denser it is, so the more fuel it needs to ignite.
You could be getting lean misfires in cold air starts, CEL comes on.
Once RPMs are above 500 computer starts fuel pump full time and pressure builds up again, so lean condition is gone, CEL off.

Most OBDII readers can be use for live scan, so can be hooked up before starting.

I'll try that RonD.

I sold my Mustang, so the tuner I had got sold as well, so I have no way right now to read the codes as they appear. I'll need to buy another hand-held OBD-II reader, as the one I had got "borrowed" by my son awhile back. It's easier to get a new one.

Truck runs great; and since these codes come and clear within a minute, and only in cold weather, it does not seem to be a pressing issue, although it bugs me not to know whats up. I like preventitive maintenance, so resolving this issue will not go on a back burner.

You can get those Bluetooth OBDII interfaces.
They get power from the OBDII connector and you can read the data on a smartphone or laptop that has bluetooth.

They are not expensive but check "app" prices for different models, some times the less expensive interfaces have expensive "app" pricing.

Meh....I'd just as soon buy a simple hand held unit.... While I'm a fan of bluetooth hands free phones to allow for both hands on the steering wheel when driving (for those who must talk on a phone while driving), I'm not a fan of paying some software company for their software/app in order to obtain a CEL code from a possibly cheaper bluetooth OBDII interface.

These are better for the live scan features since there is no cable attached when driving .

For this, I use the wife. She does the "driving miss daisy" thing during the week (drives us to/and from work), and I drive the weekends with the truck. She would be most happy to read the code(s) on the old fassioned hand held that will hopefully occur the next time the temps drop. This is one of the many reasons she has been my best friend and wife for 33 years. A keeper!

I'll even take her out to breakfast if she agrees.

I only need to figure out a better way to keep the son out of my tool box when he comes to visit (real reason: "borrow money and tools").

I seemed to have corrected this CEL issue; it ended up being a bad oil pressure sending switch.

When I swapped back to my original cluster (I had installed a cluster from an Explorer with white faced backround), the oil pressure guage was not working (on original cluster after installing it). At the same time, the CEL light was on. After about 20 seconds, the oil pressure guage went to it's center position, and the CEL light went off at the same time. I replaced the oil pressure sensor, and it has not happened since.

Weird though that the gauge always worked with the Explorer cluster and flaky oil pressure sensor, and only when I went back to the original cluster was I able to see the oil pressure gauge not working along with the CEL light on.

In checking the factory wiring schematics, I see the ground sent from the oil pressure sensor goes to the cluster gauge, as well as to the anti-slosh module, which then shows a connection to the CEL dash light. So, along with any trouble codes, the CEL light comes on anytime a cluster gauge is not working?