I have a f150 2007. I was driving to work and alarms started going off warning came up reduced engine power the engine light was flashing and the engine started running rough and as long as I was running at low speed I could maintain speed as soon as I put it under a load I would lose power. I pulled over and shut off the engine check out the engine and found no over heating. Started the truck up and everything went back to normal. This has happened several times. Each time I try to put the engine insert a heavy load it does it.
What's wrong with my engine?

 

Get your codes checked first. Might help narrow it down.

 

same thing happened to me today in my 2007 with a 5.4

 

Truck went into limp mode I would guess thats why no power. Why on the other hand it did could be a few things. When mine used to do that it was because the throttle body was sticking. I pulled it apart and sprayed it down with cleaner specifically for that. Make sure you have no power going to it because they do have a deicing strategy on and with the gear reduction inside it could take your fingers or cause serious harm. Clean it out well and do the maf sensor while your at it. I eventually came to the assumption that i was somehow getting dirt past the air filter and put a new intake on. Never a problem after.

 

have you found out what was wrong?same problem here

 

Check your battery terminals, a bad connection or a bad ground can cause this.

 

You need to have the codes pulled before anyone can point you in the right direction for any further diagnosis.

 

no check engine lights on.Only flash when it goes to low power mode,When it goes back to normal,check codes.....none to be found

 

no check engine lights on.Only flash when it goes to low power mode,When it goes back to normal,check codes.....none to be found

 

there should be codes in the history on the pcm if not i would suspect either a voltage problem or a small problem that is causing a larger problem.
like said above check your throttle body take it off and inspect it next check the maf sensor for dirt or a flim on it you can shine a flash light on it to see it should have a slight shine to it for it is a wire that has voltage running through it and when air passes over it to cool it down that is when the pcm sees how much air flow is moving through the intake tube. check your air filter as well look in the tube and see if you see dirt or anything else that is not soppoused to be in there.
check your batter terminals make sure the battery cables are tight and clean. next look at your alternator make sure the main cable coming off is tight and secure including the metal crimped on end make sure it is not loose or coming off.
can you reproduce this problem while the truck is in park by revving the engine? or only while driving?

 

can only re-produce while driving.Also,happens more often than not while using the heater.Has never done it wile not using the heater.Hmmm,I may change the temp control sensor to see if that may be it.I have heard there are 2 sensors.Maybe 1 for the heater?Maybe that 1 is malfunctioning and pegging the temp gauge sending it to low power?

 

I had a 97 with a 4.6 that the temp gauge would peg go into limp mode i ended up replacing head gaskets to fix mine exhaust gas was getting into the water when the air bubbles came in contact with the water temp sensor it'd do stupid stuff