It is an easy look see. Use pb blaster and blast the bolts and un bolt it. Run it and see if your loads go down. 50 % is high for idle.

 

wow thats great jimmy. unfortunetly they allready disconnected my convertor with the same results no power at wot. so far they have tried
mass air flow sensor, fuel filter, fuel pressure regulator, knock sensor, tps, coolant temp sensor and have said the fuel pressure is good he even hooked up a auxilary fuel pump at the filter.
and can not find a vacuum leak. they called last friday and told me to take it to the ford dealer and that is where it is at but it will be a few days before they look at it. at least they only charged me for the $30.00 worth of fuel they had to put in it and did say they would try a fuel pump
and would not charge me if it didn't fix it. the wierd thing is that on the scanner it reads wot before it is even floored have at least a whole volt
before it is floored. i dont understand that maybe a pcm trouble i'll let you all know.
thanks.
kirk shonk

 

Kirk,
If its any consolation, if the cat didnt fix mine, my next move was to a reflash of the PCM. In fact more people were leading me to that conclusion that I needed to get re-flashed.

I was telling my friend who owns a sports car shop my troubles, and some of the solution replies I had received here on FTE and he piped up and said,,, I also think its a clogged cat,,, so we tried that one first.

Thankfully it helped me.

Good luck in your quest.

Cheers
jimmy.

 

okay here is a updated if you been keeping up with this.
so i dropped the vehicle off at ford dealer last wednesday they call on monday and say i need a fuel pump and 1 o2 sensor at the cost of $990.00 so i say are you sure about that we hooked up a inline fuel pump with the lack of power results
dealer say i wish you would have told me that i'll get with the tech to rediagnose. a day latter the dealer calls you need a pcm we "think" that it is what is causing the problem. so i give the go ahead to order the part of course asking are you sure it's not a chaffed wire or a pcm ground problem
dealer says yeah yeah the technician is a compintent tech. well i'll give you all the result wednessday if fixed. by the way what led him to the pcm is that the tps reads 1 volt difference between tps & pcm well we already knew that just didn't tell the dealer but i should of at $105.00 hr diagnostic time charge 3 hr labor to find problem and insall new pcm.
the funny thing about this is that it still gonna cost me close to $900.00
must be there quota.

 

The pcm wasn't reading the tps? Or the tps was bad?

 

well it's finaly fixed with the pcm being replaced.here is the scoop hope no one has to try to diagnois this problem on there own. recap i replaced the fuel filter and maf.took to a independent shop they tried disconnecting catalytic convertor, r&r tps, coolant temp sensor, fuel presure regulator, installed external fuel pump checked for vacuum leaks & fuel pressure. they noticed tps reading wot before reaching floorboard and said i needed to take to the dealer 3 weeks down time there. so i take to ford they call and say it needs a fuelpump & 1 o2 sensor $900.00 i say the other shop put a helper pump with the same loss of power result ford says i wish you would have told me that why i dont know im paying for them to diagnois the problem but oh well he says i'll have my tech relook at it. okay.ford call a day latter you need a pcm 4 days later i get the vehicle back and it is fixed here is the write up. found code p0171 monitored datalogger while driving under load shrtft on both banks 33.5% o2 sensors drop to 0 volts. verified fuel pressure 35 psi & 2 psi back pressure exhaust under load. fuel quality good. max maf was2.8 volts at wot. back probed maf signal at pcm measure at 3.8volts while maf v pid read 2.8 volts at wot.unplugged maf allowed engine to run normal. inspected pcm connector for corrosion none found. load tested power, ground & contacted hot line for assistance replaced pcm & retested maf v pid read normal concern resolved. thats it 2 months later & $950.00 later running like a raped ape. hope this will help someone. thanks for all the support espeacilly Jimmy Pet who wasn't rude
like some people.

 

Holy Crap Kirk, thats awesome!!!
Well,,, you pretty much went through the process,,, that was the only thing left (of course).
As I said, if the cat didnt fix mine, I felt like that was my next step.

VERY glad you got it fixed, and glad its all in one thread.

Hopefully all of this diagnosis time and money spent between two trucks with identical problems (and two different solutions) will help someone else in the future.
Cheers
jimmy p

 

Glad to hear you finally got it fixed! Rep points for you

 

I'm having similar problems, any help
https://www.ford-trucks.com/forums/1...seconds-2.html
Thanks

 

what was wrong with the PCM ? just wondering what does bad in them in which it would need to be replaced and not just re flashed

 

Much thanks to Jimmy Pet- my symptoms matched his exactly except for my mileage is higher, and mine didn't start overnight.

I just had my cats removed and straight pipes welded in. Runs great again! Absolutely no pinging/spark knock/etc!!!!

 

What an outstanding thread! I just found this. Same issue but on a truck with a few more miles than anyone else's
2003 F 450 6.8 Liter
585000 current miles. I got 430k on the first motor until a wrist pin finally let go. We are at 165k on the reman replacement from Ford. Problem slowly appeared. My attempt to repair started with the MAF, then the fuel filter, then the fuel regulator and finally the pump n the tank. Had the same thought about a plugged pickup screen even though fuel pressures were within normal ranges. . I just found one bad 02 sensor (laid on the pipe and melted the connector) but do not believe it's the problem. Going to replace those tomorrow.The funny thing is with each item replaced the performance improves a little. I just feel like I've been peein in the wind. This thread made me rethink the cat. The exhaust system in this truck is ORIGINAL and has never needed any service or repair. It seems clear. I opened the passenger door then ran the rpm's up and I was not hearing the rocket ship rush of air that usually accompanies a cat beginning to plug nor was it overheating at all. It is astonishingly quiet for a truck with this many miles on it however. I even considered installing an aftermarket frame rail fuel pump as a backup booster but alas I gave up on that idea. Too many issues with wiring it up and connecting it to an already taxed fuel electrical system.

I'll post back my end results. I want my power back and won't stop until I find it. At 7mpg, it's the only saving grace about this engine.

PS, one comment I want to make for those that have not put extended miles on one of these engines. Make sure you don't run them lean. These types of problems need to be fixed in short order. I can show you photos from the old engine and how badly the valves got beaten up from years of leaking vacuum lines and running too lean. I am convinced my first engine would have lasted past the half million mile mark if I would have taken more care with it.

 

Yup. Pulled the CAT today. Completely plugged. Straight piped it temporarily while I get a new one ordered. Also went ahead and completed my refresh of everything fuel and ignition. Added all new Accel coils as well as replacement of my upstream
02 sensors. (Truck does not have downstream sensors). This has been a problem for so long that I had forgotten just how powerful this engine can be.

V10 engine has a really unique exhaust sound once you remove that CAT. We're back in business! Woohoo!

 

Yikes! That cat might still be worth some money for recycling

I always wondered, what's the best way to test for a clogged cat? Remove an O2 sensor and put a pressure gauge on it?

 

Good question. As usual I started at the wrong end of the path to work out what my issue was. I ignored all the tell tale signs pointing right at it. Loss of power slowly over time, truck running very quietly, burning smell from under truck as cat became overheated, etc. To answer your question the best way (hindsight is 20/20) is to look for pressure in the pipe before the CAT. I would not pull the 02 sensor and go drive it to see if it's better because that can set you up for a fire. I also think most pressure gauges would not be able to handle the heat so close to the engine. The next time I suspect the CAT, I would drill a small 1/4" hole in the pipe just before the CAT then lay under the truck and have someone poke the gas pedal. If the CAT is blocked, you will get a forceful blast of exhaust out of the hole, if the CAT is clear, the blast of air leaking out would be minimal. I also think they make a pressure test tool that does that exact thing through a drilled hole and also gives you a way to plug the hole once you are done.

All the other work I did before I got to this point was unnecessary. Having said that, doing the work is like doing a major tuneup and now the truck runs better than it ever has. It's FUN to drive again so I am not heartbroken about the extra expense.

Enjoy your day!