intermittent hesitation problem
Logistics Pro
Joined: Jan 2001
Posts: 3,789
Likes: 26
From: Connecticut
I get the same thing with my '86 EFI.
the sensor on top tested good, the EGR is new. and you are right the EGR will not hold vacuum when applied with the hand pump.
If I take off the electrical top and plug the EGR hole, it will hold vacuum. I even RTV'd the electrical top to the EGR and it still won't hold vaccum. It is a slow leak, probably through the electrical solinoid on top. But since the engine is supplying continious vaccum to the EGR, I don't think it is causing any plroblems.
I still get a code 31, and a shaky (new) engine. I have the Ford Emissions diagnosis manual (E-bay) and I bought a EEC IV Rotunda Breakout Box (also E-bay) the went through the step-by-step tests in the manual for a code 31.
The sensor tested good, the EGR tested good,. "Replace module" is the instruction I got from doing the Pinpoint tests.
Guess where I'm going tomorrow.
the sensor on top tested good, the EGR is new. and you are right the EGR will not hold vacuum when applied with the hand pump.
If I take off the electrical top and plug the EGR hole, it will hold vacuum. I even RTV'd the electrical top to the EGR and it still won't hold vaccum. It is a slow leak, probably through the electrical solinoid on top. But since the engine is supplying continious vaccum to the EGR, I don't think it is causing any plroblems.
I still get a code 31, and a shaky (new) engine. I have the Ford Emissions diagnosis manual (E-bay) and I bought a EEC IV Rotunda Breakout Box (also E-bay) the went through the step-by-step tests in the manual for a code 31.
The sensor tested good, the EGR tested good,. "Replace module" is the instruction I got from doing the Pinpoint tests.
Guess where I'm going tomorrow.
Thread Starter
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Posting Guru
Joined: Jul 2002
Posts: 1,147
Likes: 1
From: East Coast
I don't think the egr is very precision made, so maybe that's why they don't hold vacuum. If I gave mine vacuum with the pump and held it, the code would go away, odd...
Anyway, what module is that? And be sure to let us know how it works out! Thanks reamer!
Anyway, what module is that? And be sure to let us know how it works out! Thanks reamer!
Posting Guru
Joined: Sep 2003
Posts: 1,002
Likes: 1
From: Right Next to U
Its still won't get rid of the code 31, my 86 had the shakes too, but the computer replacement cured it, but not the code 31. I also am still getting it, 31, 10, 11. But be sure to swap yours with the same number as was on your old one, or you'll be back exchanging the computer again...(been there, done that too) I also tried unpluging the EGR. All it does is bogged down at higher speeds....and uses gas like crazy. For now, mine is running much better, but still has the problem with the egr. (also replaced everything but the sink)
Freshman User
Joined: May 2003
Posts: 33
Likes: 0
I think I am having the same problem so I am waiting to see what fixes all of your problems. It feels like a loss of power under load( accelerating or going up grades) or even like the tranny is starting to slip, but i dont feel any increase in the engine RPM. I am going to dig into mine as soon as I get the intake manifold replaced on my 99' Mustang GT 
. That should happen this week, then its time to pull of some things on the truck and start cleaning and looking for vacume leaks... Boy o Boy am i ever excited about this... And to think I would rather drink beer on my day off.... 
Did I mention that my 98" Expedition with a 5.4L sounds like it is aquiring a exhaust leak to keep me busy right up to and through Christmas on weekends...
Joy be to me....
. That should happen this week, then its time to pull of some things on the truck and start cleaning and looking for vacume leaks... Boy o Boy am i ever excited about this... And to think I would rather drink beer on my day off.... Did I mention that my 98" Expedition with a 5.4L sounds like it is aquiring a exhaust leak to keep me busy right up to and through Christmas on weekends...
Joy be to me....
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Posting Guru
Joined: Jul 2002
Posts: 1,147
Likes: 1
From: East Coast
I don't believe it. After driving with the EGR disconneced and plugged for a week or two now, I see that I am still having the same problem 
It can't be the EGR system, I don't know WHAT to do... I feel like Hank Hill when he had to take his truck to a mechanic for the first time.
Senior User
Joined: Apr 2004
Posts: 156
Likes: 0
Nick, check the carb. I was having a similar, if not the same problem with mine. I had done everything we could think of to get it to work. Finally, I took it to the mechanic. He adjusted some of the jets in the carb and now it runs like a top. I had rebuilt the carb twice and I couldn't get it right so I had to break down and take it to the mechanic, but it was only $183. So grand total of mechanic expense on my beast is now about $250 for a complete engine swap. I'm not complaining. At any rate, you might really look into the carb.
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