Surging on decel, fuel prob or tranny?

Bigsky · 10-17-2009, 02:33 PM

My 87 4x4 2.8 auto surges anytime I am off the throttle coasting downhill. It feels like if I was just touching the brake pedal every few seconds. This truck has newer brakes, and I just completed a full tuneup. The only sensor that is not hooked up in the MAP because when its plugged in the truck will not idle properly, otherwise with MAP unplugged it runs fine, but probably a little rich.

This truck has 181,xxx on it but the tranny and motor have been replaced around 40k ago by a previous owner... The tranny fluid is topped off and a nice clean red color. I am thinking I that maybe its the torque converter trying to lock up and then releasing but I don't know. Thanks for any suggestions.

So_vayne · 10-24-2009, 07:41 PM

First things first.. Figure out why you have to unplug your map sensor..

Bigsky · 10-26-2009, 11:58 PM

Yea, I hear you on that. If I have the MAP hooked up my Dime runs without throwing any codes but it just won't idle hardly at all. I think it might be my EGR and /or EGR solenoid but I haven't been willing to lay down the cash for new parts.

ddog800 · 10-27-2009, 01:06 PM

Could try and pull the EGR and clean it, as long as the diaphram is OK then you might just have some build-up

infinity96 · 10-27-2009, 02:34 PM

I know this may sound dumb but is it in 4whl drive?

Bigsky · 10-27-2009, 08:53 PM

Quote: Originally Posted by infinity96

I know this may sound dumb but is it in 4whl drive?

It helps to make sure of any possibilities, but no I don't think its in 4wd because I also fixed the indicators for the 4x4 unit recently and it indicates 2wd.

10-17-2009, 02:33 PM	#1
Bigsky Registered User Age: 39 Join Date: Oct 2009 Posts: 6 Location: User is: OffLine	Surging on decel, fuel prob or tranny? My 87 4x4 2.8 auto surges anytime I am off the throttle coasting downhill. It feels like if I was just touching the brake pedal every few seconds. This truck has newer brakes, and I just completed a full tuneup. The only sensor that is not hooked up in the MAP because when its plugged in the truck will not idle properly, otherwise with MAP unplugged it runs fine, but probably a little rich. This truck has 181,xxx on it but the tranny and motor have been replaced around 40k ago by a previous owner... The tranny fluid is topped off and a nice clean red color. I am thinking I that maybe its the torque converter trying to lock up and then releasing but I don't know. Thanks for any suggestions.
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10-24-2009, 07:41 PM	#2
So_vayne Registered User Join Date: Jun 2006 Posts: 254 Location: User is: OffLine	Re: Surging on decel, fuel prob or tranny? First things first.. Figure out why you have to unplug your map sensor..
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10-26-2009, 11:58 PM	#3
Bigsky Registered User Age: 39 Join Date: Oct 2009 Posts: 6 Location: User is: OffLine	Re: Surging on decel, fuel prob or tranny? Yea, I hear you on that. If I have the MAP hooked up my Dime runs without throwing any codes but it just won't idle hardly at all. I think it might be my EGR and /or EGR solenoid but I haven't been willing to lay down the cash for new parts.
	[Reply w/Quote]

10-27-2009, 01:06 PM	#4
ddog800 Registered User Join Date: Oct 2008 Posts: 45 Location: User is: OffLine	Re: Surging on decel, fuel prob or tranny? Could try and pull the EGR and clean it, as long as the diaphram is OK then you might just have some build-up
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10-27-2009, 02:34 PM	#5
infinity96 Registered User Join Date: Mar 2009 Posts: 28 Location: User is: OffLine	Re: Surging on decel, fuel prob or tranny? I know this may sound dumb but is it in 4whl drive?
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10-27-2009, 08:53 PM	#6
Bigsky Registered User Age: 39 Join Date: Oct 2009 Posts: 6 Location: User is: OffLine	Re: Surging on decel, fuel prob or tranny? Quote: Originally Posted by infinity96 I know this may sound dumb but is it in 4whl drive? It helps to make sure of any possibilities, but no I don't think its in 4wd because I also fixed the indicators for the 4x4 unit recently and it indicates 2wd.
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