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99 7.3 6 speed stalls on downshift coming to stop

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Old 06-23-2018, 01:29 PM
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99 7.3 6 speed stalls on downshift coming to stop

For a few weeks now my truck has been occasionally stalling when downshifting and slowing to a stop. Doesn't happen all the time , but have noticed it seems to happen more when engine has warmed to operating temperature and when on a downhill grade. When I downshift and push the clutch in , the rpm's will drop so far as to stall. Sometimes though, rpm's will drop to around 500 then ramp back to normal. Also when it does stall , I can either pop the clutch , or key start it with no problem. It has 295, 000 miles on it, and still runs very strong. Any thoughts on what my problem might be would be greatly appreciated. Thx Bill
 
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Old 06-23-2018, 02:14 PM
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It sounds like you have a sticky IPR. Last I checked riffraff had an o-ring replacement kit for it. Take it out and clean it and change out the orings and you should be good to go. Unless the coil in it is getting weak, then you would need to replace the coil. I don't think you can buy just the coil though, you have to buy the whole IPR.

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Old 06-24-2018, 09:51 AM
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Same year, same trans and had same issue. As what Baatsy mentioned, my ipr had a loose tin nut.
 
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Old 06-24-2018, 04:57 PM
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First thing I checked and tin nut is secure. Also tried replacing ipr coil before replacing ipr, and still no difference. Drove about 40 miles today and still have issue. Noticed something else today. On several starts , after engine turns over, idle is very low....not rough, just low then in 2 seconds ramps up to normal. Wondering if both are correlated, or separate issues. Always an adventure with these trucks!
One other thought though.....A couple of weeks ago when I changed my oil, I also changed the oil in my hpop reservoir . May have over filled a bit. Could too much oil be my proplem? It's not much ...dipstick reads a hair above grid.
 
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Old 06-24-2018, 05:32 PM
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Faulty throttle position sensor maybe?
 
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Old 06-24-2018, 06:56 PM
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Is that the same thing as a cps ...cam position sensor?
 
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Old 06-24-2018, 08:08 PM
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No, a throttle position sensor would abbreviate to TSS, it's on the fuel pedal. I do not think that you can hurt your HPOP by overfilling the reservoir.
 
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Old 06-24-2018, 08:26 PM
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Got something you can watch the engine with? Torque pro or forscan or similar? Icp, IPR duty cycle, engine rpm, speed and accelerator position would be good to see a graph of when the problem (s) occur. Not sure if there is an accelerator position pid on the 7.3 though.
 
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Old 06-25-2018, 07:16 PM
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I do not have anything to moniter the engine.
I do however have some new information.
In my neck of the woods today it was overcast and only got to the upper 60's - low 70's. I drove somewhere in the neighborhood of 70 miles and half of that was in the city. I did not have the issue rear it ugly head once! Every time I would come to an intersection and have to stop, I expected it to stall, but it never missed a beat! I'm now wondering if outside temperature and/ or engine compartment temp have something to do with it? Any thoughts guys?
 
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Old 06-25-2018, 07:43 PM
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Well, typically the only part this is really effected by heat like that is the IPR. Although, a cool day of 60's would not have any affect on the IPR.

This is a head scratcher, but I am following along to see what you come up with.
 
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Old 06-25-2018, 09:20 PM
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How long in miles since the last fuel filter change?
 
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Old 06-25-2018, 09:21 PM
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How many miles on your oil change?
 
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Old 06-26-2018, 05:35 AM
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5 days on fuel filter maybe 200 miles..... 3 or 4 weeks ago on oil .....maybe 1000 -1200 miles?
 
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Old 07-05-2018, 05:14 PM
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[utag=meier63]meier63[/utag], have you been able to figure out what the problem was with your truck?
 
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Old 07-06-2018, 06:01 AM
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Thanks for asking sous!
Actually, I'm still scratching my head!
Everytime I think I've narrowed it down and found the problem, it does it again and back to square one I go.... still trying by process of elimination, but gonna have to get it scanned. Found out sons friend has one.
 


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