I was driving out to the lake last week and my truck's temp gauge pegged hot out of no where and went into limp mode. At the time I was doing about 70mph on the highway. I also wasn't towing anything. The check engine light came on and the oil light too. I pulled over shut the truck off, restarted it and it went back to normal. The truck was not overheating at all. I go down the road about 20 miles and boom it happens again. It did it about 15 times during my 260 mile trip through the desert at night. So I get it to a shop out at the lake next day and they said it was showing a code for cylinder head temp. So they replaced that sending unit along with the water temp sending unit and cleared the codes. We go to back out for a test ride and pegged hot again and returns to limp mode while reversing out of the shop. #6 cylinder showed 86 misfires and #10 showed 1. So they replaced the #6 coil, cleared the codes and the truck drove fine all weekend. Last night I'm 20 miles into my 260 mile trip home and it freaking goes off again! I flipped open the hood, disconnected the cylinder head temp sending unit and the truck went back to normal. I drove it home with no issues. I have no idea what the heck is going on or what to try next. I basically have to take it to a new shop here around home and start over again. Has anyone had this same experience or any ideas to what my problem is?

The codes is threw at the shop were P1285 and P1299

Thanks,

 

My truck is a 2000 F-250

 

I heard this once or twice at V-10 forum during almost 10 years (may be one was an RV owner). I do not recall if anybody reported back with a solution .

Is it running OK (good power and no CEL ,no limp mode) once you unhooked the "cylinder head temp gauge" ?

May be try to verify the functions of all "cooling system components" , like fan-clutch , thermostat , radiator not clogged , water pump circulating, check radiator temperature with non-contact thermometer ,etc.

Good luck,

 

Before you go any further replace the stat and only use a motorcraft stat...

 

I've spent hours searching the web with no luck so I resorted to starting a thread. I did find a thread about a v10 powered RV and you are correct, no solution was reported. I will try to send that person a private message once I find the thread again.

Yes. It ran fine once I disconnected the cylinder head temp sensor. The CEL remained on, but it has not gone into limp mode or had the gauge peg again. I actually drove it a few miles today and no problems other than the CEL on.

I will try what you suggested. Another person recommended I check the plug harness for a shorted wire. When I called the tech who looked at it last week he said he did that, but I guess I'll just look again.

 

Ok thanks!

 

What BigPipes said!
That is a typical overheating thing and it is rarely the senders etc. It seems like it's not that hot but it is. That limp mode/failsafe feature is great to have. A 195* is the correct one for that. I went through the same thing of maybe this, maybe that but my thermo was new but not a Mtrcrft so it threw me a curve. Don't disable the failsafe feature in any way, it's there to cool the engine and save it. Get back to us.

 

Ok. Thanks for the info. I will stop by Ford and get a new thermostat today.

 

do you have a cat coverter? symtoms are consistent with a clogged one. if you have one and are burning oil..its probally clogged. cat coverter cleaner could buy you some time.

 

Many parts stores have them too.

 

Yes I do. How do I clean it?

 

Do the thermo swap first and don't drive it with any wires unhooked.

 

Change the stat first then worry about the cat, My cat was almost 100 percent plugged and it never once went into reduced power mode..

 

Update:

I changed the thermostat Sat am. I drove the truck around town Sat and Sunday and all has been well so far. I need to get her on the freeway. I'll probably drive the truck to work tomorrow. CEL is still on, I need to get it to a parts store and borrow a scan tool to clear the codes.

 

It should be OK now. Try dis-connecting/re-connecting the battery to get rid of the code.