I have a 99 F250 SD PSD with 307,000 miles on it. No issues other then a little oil drip.

Problem started about 3 weeks ago while I was running down the road 65mph I caught a red light and like usual went to drop a gearand when I pushing the clutch in the rpm dropped like suppose to excepted they dropped so low to the point the truck stalled itself out.

I missed it in the beginning it has a 6 speed manual trans.

Everyone tells me dont worry about it just use the brakes. (I hate changing brakes) id rather down shift and use breaks as little as possible.

It only did it a few times when it first started. But now its gotten very consistent with stalling out so out by the rpm dropping to low when pushing the clutch in.

I was hoping if something was really wrong it would throw an SES lightbut no such luck. I have put Iit on the cose reader but the only one I ha e laying around is a chear 100 dollar centec job from the local Harbor Freight.

I was thinking maybe a CPS? Figured that would throw an SES light.

Now it also runs real rough in the morning when I firat start it up and drive it a bit until it warms up. (No its not cold here yet, it hasnt dropped below 70 at night in the last couple weeks)

Anyone with some ideas of what it might be would be excellent and great appreciated. Im at a loss without any time of SES light or code to start from on this one.

 

CPS doesn't always throw a code, but this doesn't sound like a CPS issue. So the rpm's just drop off till it stalls when trying to downshift? As in drops off so fast you can't get the clutch back out in a lower gear before it dies? Does it happen at every down shift or just between certain gears or at certain speeds? Can you just pop it into neutral and keep it running?

Is the engine oil full? When was it last changed? Any additives in the oil?

 

maybe ipr or icp reading bad?

 

I threw a CPS in it this afternoon quick just to see if it make a differennce and it didn't.

It doesn't do it all the time. It's very intermittent, I could be cruising down the road 65 mile an hour running around 1800-2000 rpm shove the clutch in to downshift to slow up to get off a ramp or what ever and the rpms will dive right down before I even get a chance to grab the gear and it stall itself out. I could be putting along in 2nd or 3rd gear going through a development shove the clutch in to stop and it stalls out. If I shift it without the clutch (which o do often now cruising down the road at 60 and catching a traffic light and the truck stallimg out when i shove the clutch in sucks) anyways.... if I shift withoutvthe clutch of course it doesnt do it or if I jam it in gear real quick and get back on the throttle it wont do it.

I change the oil and filter every 5000 miles and fuel filter every second oil change. I dropped the tank the other week and cleaned out the two hidden screen which where plugged up pretty good but that didnt make a difference either. I dont usually use any type of additive but I did use some Lucas stop leak in the last oil change to see if it cleares up an oil drip.

I had the HPOP out two weeks ago and put all new O'rings on everything. The only thing I didnt mess with was the IPR.

I have a bit of an oil leak on the drivers side valve cover and one of the plugs on the hpop is still got a little drip to it.

Is there a way to check how much pressure the HPOP is getting? Could it be losing pressure causing the problem? Im at a loss here where to go next with it.

When you first fire it up in the morning it doeant idle rough but once youre running down the road it runs like a cylinder is dead until it warm up good then it clears itself out and runs fine.

Do the 7.3's have crank shaft position sensors on them?

I really dont know im at the point where without someone looking at it that knows a good bit about the 7.3's or had the same problem im at a standstill.

I also couldnt figure out why I would run out of fuel at a quarter tank, turns out the pickup tube in the tank is missing. Problem there is finding someone at the auto parts stores around here that know what youre talking about, unless its a honda civic they dont have a clue.

 

You can monitor HPOP pressure with a scanner that can read live data like AE or with a gauge that can read it like the Aeroforce scanguage II.

If it starts doing it on a more regular basis, you can unplug the ICP sensor and see if that makes a difference, but if you never know when it will happen it's probably not worth trying.

If you're going to mess with the fuel tank, you're probably better off doing the hutch & harpoon mods than trying to repair a broken pick up foot. Welcome to guzzle's In-tank Hutch Mod Web Page

No crank sensor on the 7.3, just the one that reads the cam.

 

Now its doing it almost every time I go to stop.

 

Try unplugging the ICP sensor then and see if that changes anything.

 

where it is effected by the clutch only it may be a good idea to check the crank end play too see if it is in speck.

 

Currently working on a friend's 2001 F550 6spd and it's doing the same thing. EXACTLY. Never know for sure when it'll do it. Mainly seems to happen coming out of a higher gear and like described above, it drops RPM so fast that you can't get it into another gear in time before it dies. I have been through the oil system, fuel system, etc and there are ZERO issues there. It was doing it before I started working on it, and it is still doing it as of last night. Maybe only 1 time here and there, but it's going to get someone in a jam when it dies with the horse trailer on behind it.


The other thing I noticed is that you cannot start the pickup without the clutch being pressed in. Even if the trans is in neutral and the parking break is set, it will not attempt to start unless you press the clutch in too. Just this morning it all dawned on me that it all might be neutral safety switch related. Or something with the clutch setup. No codes but not right. When it stalls it acts like it would when you bog down a stick shift and it dies. And realizing that it doesn't allow you to start it without the clutch makes me think that it's something within the clutch pedal, NSS, or master.

Any idea on bringing up an old thread!

 

It's designed not to engage the starter unless the clutch is depressed. That's completely normal.

 

I was wondering about the safety switch as well. Perhaps a "flat spot" in the switch contacts at mid stroke??