Good evening gentlemen. I recently bought a used 2007 F150 Crew Cab 4x4 with the Triton 5.4 engine (88,000 miles). I got in it yesterday morning to go to work, and as soon as I stopped at the first stop sign about 50 yards I from my driveway, the truck began to idle rough. It sputtered and stumbled as I accelerated too, with the RPMs jumping to 2500 or so, but only going 10 miles an hour. I thought it was going to sputter to to stop when I finally got up and going and it shifted into overdrive. The "check engine" light came on too.
I drove it to Autozone today and had them pull the codes, which I have included below. On the way back home, after the truck had reached operating temperature, it ran A WHOLE LOT BETTER. I checked some previous posts in the forum, and they seemed to suggest the VCT solenoid might be bad. However, when I checked the Repair Guide section on Autozone.com, I found the following info:
"The PCM receives input signals from the intake air temperature (IAT) sensor, engine coolant temperature (ECT) sensor, engine oil temperature (EOT) sensor, CMP, throttle position (TP) sensor, mass air flow (MAF) sensor, and CKP to determine the operating conditions of the engine. At idle and low engine speeds with closed throttle, the PCM controls the camshaft position based on ECT, EOT, IAT, and MAF. During part and wide open throttle, the camshaft position is determined by engine RPM, load and throttle position. The VCT system does not operate until the engine is at normal operating temperature. The VCT system is enabled by the PCM when the correct conditions are met. A difference between the desired and actual camshaft position represents a position error in the PCM VCT control loop. The PCM disables the VCT and places the camshaft in a default position if a concern is detected."
So, the truck runs bad when it's cold, and a lot better when it's warm. Does that mean the problem would likely be the PCM since the VCT isn't activated until the engine is warm, and it runs better when it's warm?
i was reading the other day on 1 of the forums a similair problem and the person was advised to dis connect the engine oil temperature sensor. My guess from what you have posted its 1 of your temperature sensors acting up esprcially when you say it runs better when warmed up. If a coolant sensor is acting up usually that will make an engine run rich I would be inclined to get a manual and start checking those sensors
Look to your sensors, the PCM will code a problem. Check their plugs as one may be not pluged in ok, or wire damaged. If you do the HEC test , Hold in the reset button and turn the key to run, don't start, the first test will be the gauges, the hand will sweep all gauges, if they dont pass check the sensor first for the faulty gauge. navigate all the tests, if you find one not passing you can start the motor and run it while running. Cluster test will also give you error codes DTC's as you navigate it. Some info codes are engineering and are for the cluster diagnostics, but you can see/learn alot about the truck anyway. Mainly you are seeing the CanBus in operation. If you do not pass then the CanBus is in question (PCM)failure code.
Replaced the oil pressure switch today. Undid the battery for 30 minutes to reset everything. Ran fine. BUT.....it was warm today, so I don't know if that actually solved the problem or not. I also pulled the MAF sensor and PCV valve. I don't know how to test them, but they looked alright. Same for the camshaft position sensors.
I'll report back again sometime next week.
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