Hi all.

Sorry for the long tread, but I think it is necessary to provide some background as part of troubleshooting the problem.



I have a 2015 F150 3.5 litre ecoboost XLT 4x4 with approx 65,000 kms (40,000 miles) on clock. Last week the engine warning light came on. Ford service centre said the computer showed the O2 sensor was the issue which was replaced and seemed to be fine afterwards.



Today I was driving the F150 since morning hours around the city, and because of the current high temperature I don’t switch the engine off when parked when I do quick stops so that the AC can run to keep the inside cool. Around mid day I parked at a coffee shop and got a take away coffee. When I got in I noticed the engine was not idling and thought it was strange but thought perhaps I switched the engine off. I started the engine which started normal, but then when tried to accelerate the engine was sluggish, stuttering, struggling to get power to drive away. I tried to rev the engine but no luck. I managed to get going but the engine lost power and died after probably 100 meters. Again I started the engine and it started normally. This repeated probably 4 or 5 times until I got home. Luckily I live about 2 blocks away (2.5 kms / 1.5 miles) from the coffee shop. At home I started the engine and again started normal, and revved the engine and the engine was fine (well I assume it is fine). There were no warning lights on the dashboard. Strangest thing, the transition temperature was at zero, which is impossible since the engine has been running almost non-stop for 3 hours. The engine oil pressure and coolant temperature gauges was normal.



I live in Qatar where the temperature is currently between 43 to 50 degrees celcius (109 to 122 degrees fahrenheit).



Any advice what the issue could be? The service I get from the Ford service centre here in Qatar is not the best, anything out the ordinary i have to troubleshoot myself. I (hopefully) don’t want to end up having to replace several items (leading to unnecessary costs) due to the technicians guessing what the issue might be.

 

Not to sound insulting but your also asking for guessing, here.
Nothing like guessing from 9,000 miles away, with nothing specific but high ambient to work with.
My guess is it's a reaction to the high heat. No kidding!
Some basic baseline thoughts are; when the truck is not moving only the Fans are available to cool the radiator with the high ambient outside air, in addition the A/C also generates heat in the Condenser also located with the Coolant Radiator. Both these have to be cooled by the Electric Fans that move that hot air back over the engine and the truck is not moving at the same time for any advantage that might have in those high ambient temps..
Lets take a look at a for instance; If the coolant temp is at 220* when the Ambient is at 122* , that only leaves 98 degrees difference and with the truck not moving to even take advantage of that much air flow. Are the Shutters located in front of the Radiator, opening properly?
In addition, the CAT Convertors one for each bank run at close to 800* under the truck to add heat underneath. Harness may have been damaged.
No way of knowing what the design limits of a combination of conditions like this will handle. It's extreme in my opinion and may cause the PCM to put the program control into LIMP mode.
There has to be a code set to offer an initial direction to go in.
The live data should be looked at trying to detect an out of limits reading as a direction to go in.
I'm not surprised at all that something will get "cooked" under those conditions.
Don't let the vehicle idle under such conditions, that long in total.
Do let us know how it all works out because this is a one off situation we seldom see or reported.
Good luck..