My new '08 FX4 has gone to a crawl. Went to Shreveport LA state fair last weekend and back with no problem. Put 400 miles on it. Filled up ULSD. Then wife drove to buy feed and truck won't rev over 1750 rpm. Sounded like water in fuel or a miss. I got it home. Drained frame filter.Showed no water. Added ULSD safe conditioner to tank and engine mounted filter. No miss @ idle - 1750 rpm. Engine light always on and doesn't flash. Runs 20-40 mph tops. Otherwise seems fine. Have an OBD II scanner that plugged up but didn't retrieve any codes. Assistance appreciated. Local dealer mad that I drove to Dallas and bought truck $7K cheaper.

 

You need a CAN compliant OBD II reader in order to get your codes, that is probably why none showed up. I was going to say your truck is probably in Regen mode, but I don't think it would have lasted that long (and I don't know if it starts back up if you shut the truck off).

You should scroll down a little further on the main forum page and look for the 6.4L forum. You wil probably have better luck finding help in there.

 

sounds like the truck has gone into a fault mode to limit power. You will need to take it in and get it read. If you are having a problem with the local dealer I would call ford directly at this link:Telephone and Mailing Address - Ford

 

Thread moved to the 6.4L forum

 

Thanks.Hadn't been here in bout 2 years so lil rusty. Filters were changed on schedule. No problems other than key switch cylinder (somebody broke master lock key off in keyhole) and sometimes 4x4 not engaging (light on but front didn't pull). Truck starts and runs fine other than miss starts @ 1750 rpm. No power. Guess I could limp to dealer 20 mph. Or maybe pull battery cable and see if reset. Then go look for problem. Thanks. Get about 11-12 mpg has been normal with all increased emission stuff. Plenty of power until now.

 

one injector bad on these trucks will KILL power. if your dealer wont help you, then no wonder you went somewhere else.

 

either fuel or cooler related. Very possible it could be a fuel cooler failure or EGR cooler failure too. Don't feel back 3 of 25 08s we have are down w/ complete fuel system failures.

 

LMAO you obviously have no clue so hush dude. Probably is caused by a bad EGT Sensor, EGRTA sensor failure will cause derated power and a maximum speed of 50 MPH but will seem like it will never get there. I will bet one of the exhaust sensors is your problem.

 

PSD6 is probably correct. That happened to me and it was the egt sensor on the drivers side somewhere. They had my truck for three days when it happened to me. New sensor out of box was not functioning so they had to order another one.

 

Yes, the EGRTA Sensor is the EGT Sensor located on the up-pipe to the turbochargers. Fairly simple fix just a parts failure it happens.

 

egt sensors wont cause a miss.

 

Your engine is in safe mode. This feels like a miss, runs horrible and wont go full speed. the biggest causes ive seen that cause this are overspeed and overrev codes. The only way to clear these is with a factory scantool. take it in and see what they say.

 

don't want to sound like a complete idiot, this happened on my 06 F150, throttle position sensor....

 

Okay. Thanks. Possibly overspeed or overrev. Truck tops bout 95 mph with or without trailer load cattle behind it (bout 14000 lbs). Revs are limited too but understand might be possible to downshift @ too high speed and cause this. Have teenage kids but they weren't driving when this happened. Sent to dealer Tues. So far a sensor or valve is out on high pressure side of fuel pump.They ordered part and had to remove turbos and intake I believe. Said 2 wires rubbed and shorted together but is internal in engine. Warranty will cover it and should get it back and know rest of details late Fri. Sounded to me like the engine was getting too much fuel so management shut off fuel @ 1750 rpm. May not be technically right but I'll try to get better understanding later.

 

Ok. seems there is a valve thats part of hi pressure fuel pump system and has 2 wires that is under one of the turbos and intake manifold. The wires are insulated but this insulation may wear causing the valve to ground out and cause the comp to go into limp/slo mode. I signed some papers for warranty but didn't get a copy. Can't say how much it would've cost or what other parts were involved. Kno it took 2 weeks and they had parts in 3 days. But only one diesel mech and bunches of diesel trucks to work on, something about a funeral and think the mechanic did a fair job but was probably distracted by funeral or personal reasons. The new valve had wires covered in braided plastic or wire sheath so shouldn't happen again soon. No over rev, overspeed, no bad sensors or any such thing. Bad part from design on. Thanks for input tho.