Ok, new to posting in the forum so I will try to make this long enough but short enough! I have a 1999 F250 SD 7.3 PSD, 4x4, Automatic, stock with 171000 miles on it, daily driver.

Problem: Several weeks ago I drove the truck on a 200 mile hwy trip, it ran fine until I was pulling into my driveway and it sounded louder than usual and idled a little rough, I killed it and went in the house. After it about 3 hours I went to start it and it wouldnt start, it would turn over but not start. I checked a few things and finally unplugged the CPS plug and sprayed it with some contact cleaner and plugged it back in and it started up! Drive it for the next two day with it starting but running a little rough but not terrible, thinking I need to replace the CPS. On the third day it starts acting like it is running out of fuel or something, really idling rough and loud and no power or even response as I mashed on the pedal and finally it dies on me. I replace the CPS and it wont start. I have a mechanic friend scan it and it shows the IDM. So I order one of those and it takes about a week. I know Im sorry. I receive the new part put it on and it starts and runs great for 4 days. On the fourth day it does the same thing rough idle and feeling like its fixing to run out of fuel and then dies? I pull the IDM send it in and they say its perfect. It has set for a week at this point again. I put my old IDM in and it starts and runs so I run it to my mechanic friend for him to scan. It shows electrical interruption. So we find a broken positive terminal on one of the batteries, fix it and of course it wasnt that simple. So we scan it again and the first time it showed cylinders 1 & 3 being bad. The next scan shows cylinder 8 and not 1 & 3?? He finally said he thinks its the valve cover gaskets with the connectors?

Whew! If anyone is still awake after reading all that I would greatly value your input as my mechanic friend admitted that he was guessing??

 

the plugs on the VC may just be lose on the inside it happens a lot.

 

Me thinks you may not need an IDM.....

This thread should help you out.

https://www.ford-trucks.com/forums/9...lve-cover.html



By the way Welcome to Ford Truck Enthusiasts.

 

Welcome to FTE. The only code you got was for the IDM? When it's acting up, how rough does the engine run? IPR issues can also cause problems when the engine is hot. Might be as simple as some worn o-rings on the IPR.

 

Thanks guys! This site is awesome!

The only code that came up the first time it died was the IDM. When it was running it threw up several codes.

My question to the thought of the plugs in the valve covers is why would it run fine for a while and then die, after it is warmed up to operating temperature? Sounds maybe more like it could be the IPR O-ring thing?!

 

Does this sound like your problem?

https://www.ford-trucks.com/forums/9...d-sensors.html

 

I have seen people mention on the earlier 7.3's that some wires on the UVCH rub on the push rods and can rub threw, causing a ground, causing all kinds of weird running conditions and codes. I would at minimum pull the valve covers and have a looky at the connections and check to see if any wires are rubbing anywhere and if any rubbed threw.


Some people also have weird problems when the main harness connection (on front, top of drivers side valve cover) comes loose or has a bad wire in it.

 

 

Thank you all for your help! I have had another thought as I have tried to drive or at least start and let run to diagnose further:
If it will start and run after setting or cooling off and the oil has thickened up and then as the motor warms up and the oil gets thin is starts to act up I wonder if it could be an O ring oil related problem, as in thinner oil gets by weaker O-rings?!?! What do yall think? Would the IPR act this way?

Thank you for helping and putting up with me as I have slow responses!

 

The oil pressure stays great all the time btw!

 

Yes, leaking o-rings can cause this type of symptom. IPR o-rings are the first place to check. Injector o-rings could be a possibility too.

This is assuming the engine oil has the proper rating and isn't past due for a change.

 

Thank you F350-6!
Oil is great! I will replace and report back!

 

I replaced the IPR last Thursday and it has been running great! I hope that was it!! Thank you all for your help!!

 

What did the old IPR orings look like?

 

They looked a little wore but werent broken.