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00 F350 won't go past 60mph, got me stumped

31K views 20 replies 12 participants last post by  1970something 
#1 ·
Okay I have been working on the neighbors 00 F350 CCLB 2wd dually for the past few days & I'm stumped. He said that it won't go past 55mph & feels like it's running out of fuel or has a gov. He bought the truck brand new & has only put 96k on it since 00. So far he's had it to 2-3 diffrent shops & they are all stumped as well. Replaced the IDM, fuel pump 2 times, dropped the tank & made sure that was clean, put a new pickup screen on, blew the lines out, replaced the fuel filter 3-4 times & no luck. It has been doing this since Feb.
I unhooked his EBPV on a random chance thinking that was his issue, but didn't change a thing. Put a scan gauge on it & pulled up p0603 & p1211. The truck cold starts & warm starts fine without any smoke. I swapped in a good IPR yesterday & went for a drive with him. For a stock truck it pulls hard up to 55 but then will sit there with the converter locked in 3rd gear at about 2700rpms & won't go any faster & feels like it's missing slightly. That's for the first 2 miles or so, after that it starts loosing power & won't run up to 55 as fast anymore or even want to do 55 to begin with. The IPR didn't really make much diffrence except in how it idled & seemed like it starts alittle faster.
So I swapped PCMs with my Ma's 00 since they are both NVK4 & we got it up to 60mph this time. The problem is the roads iced up so we couldn't get on it without fishtailing all over the place. It didn't seem like it was loosing power as bad after a 3 mile loop but then again couldn't get on it too hard. It will hit 3000rpm in 2ed gear but won't rev past 2700rpm-2800rpm max in 3rd with TC locked. I was going to hook up the chip & see if it would allow it to run past 60mph but the roads were too icey.

I did hook up the scan gauge & watched ICP pressure & duty cycle while driving. No data log but just watching it on a few runs came up with this-

2500rpm
3000psi
37% DC
2700rpm
2900psi
38% DC
3000rpm
35% DC
The two top runs were in 3rd with converter locked WOT doing around 50mph +/-

I'm going to get a fuel pressure gauge today & going to try hooking that up tomorrow & see what it does. Other then that I'm running out of ideas. Battrey voltage is 14v when running & it cranks over fine, not the fastest but faster then alot of strokers I've seen. He used to be able to hook up to a 42ft gooseneck horse trailer & cruise at 70mph+ all day long & has had it over 100mph before. It's just been doing this defueling thing since Feb & NO ONE has any clue. If fuel pressure checks out fine I don't know where to go.

I saw the ABS light on but didn't think anything of it since I know plenty of trucks with it on for one reason or another. Someone suggested that it could be some ABS issue, I don't know but I'm not ruleing anything out at this point.
 
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#3 ·
It's not, I confirmed that before unplugging it. He called today & told me if he eases into the throttle it will come up to speed. But then he's on it demanding power (like trying to get out in traffic or get up a hill) it will hit a wall.
 
#13 ·
Okay I'll check pressures tomorrow. He just had the tank down & blew the lines out recently, this truck gets driven locally 1-2 times a week.
No smoke on start up, when he pinned it hard on one run I did see a brief puff of white then it vanished right away.

did you try swapping cps?
No not yet, he has been running the grey one for a couple years without issue. I don't feel a CPS would cause this issue either.

Are all of the sensors working correctly? Does it ever shift to OD?
Far as I know everything is reading correctly & no codes. It threw a ICP high/low before I swapped the IPR. Since i swapped that I haven't gotten that code again. Yes it will shift into OD if you let off or drive it like an old man.


Someone else suggested doing an oil change, I figure it can't hurt since it get's changed 1-2 times a year. The truck sees 5-10k miles a year & that's about it.
 
#9 ·
did you try swapping cps?
 
#12 ·
What about the little check valves in between the fuel line and the head. Seems to me, if they were slightly cloggled, easing into it would make the truck happy. Jumping on it would make it fall flat on it's face.

Mentioned these to Cat earlier, just want to hear what everybody else thinks.

This issue would also never set a CEL.
 
#15 ·
Only spare I have to swap is a blue one off a 466. :doh:

Could go take the bus into the dealer tomorrow & get my free grey one. I love my dealer, sign paper & they hand you a free one & let you keep the one in the truck
 
#16 ·
Check the fuel pressure @ WOT like I said.

Also to determine what Arsilly said above, pull the fuel pressure out of the heads opposite of where they are fed. (So passenger front, Drive Rear). It's 1/8" NPT... so if you get that 1/8" MNPT x -04 MJIC you can do that and the OBS fuel pressure checks like I was telling you about.
 
#17 ·
Okay I think the award goes to Andy, I pulled the check valves off & gutted em. Hooked it back up & it runs like a mofo, took it up to 80mph a couple times & called it good.
 
#18 ·
No that award goes to Larry's Little Secrets. Glad you found it. Glad I remembered about those little check valves.
 
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