My 94 is acting weird and I'm having a hard time diagnosing it.
Symptoms are oil pressure low after warming up, but not all the time.

When oil pressure is low and I come to a stop, it runs rough. No smoke or anything but rough. Then sometimes, like a switch has been flipped, it smooths out and oil pressure comes back up on the gauge. Sometimes the gauge stays low though. I don't really trust the gauge much.

In trying to diagnose this I pulled the oil filter to check the valve. It was loose and about to fall out so I restaked it in place real good. I checked it this morning and it's still in there.

I swapped the ICP sensor with my 97 and put an o ring kit on the IPR valve.

Tried unplugging ICP when it was running rough. It ran different but still rough.

Changed fuel filter with a new motorcraft, also cleaned the FPR and the little filter bowl under it and the FPR screen. Verified fuel pressure at about 60-75. Needle bounces too bad on this one to be real sure. It is shimmed already. I also put 100 gallons worth of power service, silver bottle, in the tanks at last fill up. The fuel hasn't been so great here lately. Even my new tractor doesn't like it.

Oil has about 1500 miles on it and is rotella synthetic 5W40.

Today, I pulled my horse trailer with about 2500 pounds of hay in it, 12,000 pounds total for the trailer and it was really running like a dog compared to a couple weeks ago. It never did the crappy idle thing but the power sure wasn't there climbing hills.

Any other ideas or things to check on the off and on idle problem? I really need to figure this out now. We've got several long trips to go on in the next couple months and don't want to break down.

 

You may try cleaning the IPR. Though that shouldn't have anything to do with the gauge pressure ..

 

I blew it off good while I had it out for the o rings. Do they come apart any farther for cleaning at all?

 

Yes , There are some pics of it some where I'll see if I can find them .. Sometimes the IPR is just worn out ....(sticking)

 

You don't know if I can use one from a 97 do you? One has the edge filter and the other doesn't.

 

I can't say , other than the filter , what may also be different ..

 

If the IPR wears out what does it affect??? What is it function completely.

 

Before I went to pick my wife up from work yesterday I swapped the Cam sensor with an old spare I had, a black one.
I took out the gray one which I had to put in to replace the 1 week old black one that Ford put in when it died.
The power is back for sure and I didn't feel any rough idling on that trip but I'll keep an eye on it and see what happens.

 

The symptoms you described were either IPR, ICP or cam sensor. I have heard that international's new cam sensor is really good for our trucks. I bought 2 of them to keep in my trucks for spares. I haven't tried them in either one of my trucks yet.

 

My truck started doing the same thing. I haven't had low oil pressure, just real rough running, like it is missing. I got codes P0344, P1211, P0236 and a couple others I know what are. I have only noticed it when its running in the morning. I have to make a 50 mile round trip this morning and I'll see how it runs. I haven't done anything yet, have a spare gray cam sensor, we'll see how it runs. I was told in my check engine light post to check icp wiring and cam sensor wiring and sensor itself. Don't mean to hijack your thread RRanch but looking for more ideas. BTW which sensor is the icp? I think I know, but not sure.

 

When looking down at the engine, it is on the drivers side head near the front. It's real easy to see and get to.

 

That's what I thought. Thanks much

 

That was the new international gray cam sensor I had in it. It was only a couple months old. I just took my wife to work again and noticed some more things going back to the black one. Throttle is much more responsive. Shifting easier now too since I can control the RPM easier. My synchros are gone.
It seems like it fixed it. I'll keep my fingers crossed. I haven't heard it running rough yet.
The oil pressure gauge went down a couple times on me but I'm really thinking it's just a crap sender on it now. It's a new one too.

 

I think you are on the right track with the CPS. Check the connector that the CPS plugs into. My connector needs some TLC and it will start running bad until I jostle the connector a bit. Its on the list of things to fix when I put the intercooler in.

 

It acted up again today pretty bad. I was running 70 down the highway, pulled into a store and was idling while my wife ran in. As soon as we stopped the engine started running really rough and stayed rough till I got it over about 2000 rpm. I didn't have my meter with me there but when I got home I checked the ICP. First I unplugged the IPR and it died. That's good, means it's not sticking I guess.
ICP voltage at WOT was 2.87. Idle was .987.
According to something I read on another site if the ICP pressure is over 1600 psi at idle then it's probably a foaming problem caused by a worn low pressure pump or cracked pickup.
What I don't understand is why would a worn pump or cracked pickup make the icp go higher? I'm just trying to figure this out.

According to the Ford CD manual I have 2.15 volts on the icp is 1600 psi. If I was 2.8 then that is more than 1600 I should guess.

Can anyone help me figure out where the problem is before I tear into it and waste money? My oil is rotella synthetic 5w 40 with 1700 miles on it. I already changed the cam sensor and ICP sensor.