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Discussion Starter · #1 ·
Hey, so 96 7.3 powerstroke 240K miles. I have an intermittent lope at start up. And very Intermittent. It might do it two or three starts in a row or it may not for 2 weeks. Give it a little pedal and its smooths out. I'm interested to know if anyone has a write up on the problem, or knows specifically what is happening in the engine when this happens. I'm not interested in hearing a bunch of sensor acronym's. I don't just want to know what fixes it, I want to know WHY. I don't think it is fuel pressure, new pump and I fixed the leak. Anyways, thanks in advance.
 

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Many times on these electronically controlled engines, it is not just one simple fix or problem (hate to break that to you). If it is an automatic, it can sometimes be due to the transmission range sensor (TRS). Usually if it is that, if it doesn't do it when starting in neutral, that's a good indicator of a bad TRS. That doesn't help you out a lot since it is an intermittent problem. Does the CEL illuminate when it happens? Is it on the first start of the day or can happen on any start? Does it only happen when the temperature is low? Cheers!
 

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On Patrick's idea, try starting it in neutral for a while. 'Course, it'll be hard to say for sure with it being intermittent, but if it doesn't lope with several starts over several days by starting it in neutral, that would indicate a problem with the switch on the tranny.
 

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I would've guessed the Injector Control Pressure sensor.

My theory is [on startup], the ICP misreads the oil pressure as being too low. That causes the computer to jack the pressure. Then the ICP suddenly accurately reads the pressure (which is now too high for the rpm). That causes the computer to drop the pressure. Then the ICP again misreads the pressure, and the cycle starts over again.

It's just a w-a guess. You could kinda-sorta test for it by starting it with the ICP unplugged for a while. Or get/keep a scanner on it and watch the IC pressure.

Intermittent problems are no fun!
 

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Discussion Starter · #7 ·
I think it might be the TRS. It started to become less intermittent so I tried it in neutral, no lope, park lope, neutral no lope, several times. So thank you. I'll repost later when I'm certain.
 
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