My 2005 Aviator with the 32 valve DOHC engine throws a lean condition code and surges when trying to accelerate in hot weather after I stand on it to get by another vehicle. When I accelerated that time it worked fine, but then the cel came on, and now when I try to accelerate it surges. It idles ok and cruises along ok.
It happened last week too on a 2 hour ride in hot weather and the dealer tech couldn't find the cause. He suspects low fuel pressure but it didn't show that when he scanned it.
I don't know if it's due to hot weather, we haven't had cold weather to test it.
Any ideas? Thanks.

 

Just fixed a problem on an 04 2v with 150k. The throttle position sensor went put completely and it acted like it was always at half throttle. Seen them become intermittent and cause surging.

 

Also just had an old Honda with a failed main relay. It's been 95+ in MD. Old electrics and battery fail Wag more commonly in hot weather.

 

Took it back to the service dept today. The tech loaned me his scanner and showed me how to set it up to watch fuel pressure.
Had the truck out this morning in 79 degree temp and when I punched it down the pressure dropped to 20 kpa (2.9 lbs). It didn't surge but it sure didn't accelerate either.
I will test it again this afternoon when the temp is supposed to be over 90.
If it falls flat, it will be interesting to see the pressure.
Normal pressure is 270 kpa (40 lbs).
When I got home it was varying between 302-317 kpa (45 lbs). A little high!
There is a sensor on top of the fuel rail that reads and controls pressure by controlling pulse width on the pump. There is no return line to the tank. I hope it's the sensor and not the pump.