87 302 surges during while slowing down

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Sep 11, 2004 | 05:47 AM

jotom

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87 302 surges during while slowing down

Hi,
Appreciate any help with this problem. Truck runs good but when I take my foot off the gas to coast the engine starts to surge and the transmission (AOD) starts to jerk as it trys to down shift. Actually I'm not sure if the engine is causing the difficulty down shifting or the transmission is causing the engine to surge. Thanks in advance for any input.
jotom

Sep 12, 2004 | 08:36 PM

hsfbfan

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I'm having very much the same problem on my '88 351. At idle sometimes it will feel like its going surge forward. When it is doing this I shift into Neutral or Park the engine races way fast. If I kill the truck and restart it is normal.

Any suggestions? There is no difference in driveability.

Sep 13, 2004 | 07:05 AM

02FX4Dude

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Joined: Aug 2004

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From: Waukesha, WI

On my 87 F150 I had problems with the engine racing when coming to stops, tranny(c6) shifting back and forth when coasting(around 35-40mph), and racing when shifting into park. It turned out that the throttle body was the problem, the springs were so corroded the throttle would not close all the way when I let my foot of the pedal. Actaually I think one of the springs was broke...Don't know if that's what is causing your problem but might worth be checking.

Brian

Last edited by 02FX4Dude; Sep 13, 2004 at 07:10 AM.

Sep 13, 2004 | 10:43 AM

Kemicalburns

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Joined: Jul 2002

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From: Bend,OR

clean the iac valve located on the side of throttlebody. then replace the tps sensor. give the engine a tune up with some good wires, cap, rotor and autolite plugs. get the cheap ones they work the best. set timing and you should be good to go

late

Sep 13, 2004 | 11:12 PM

hsfbfan

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You're gonna have to help me. I understand tps is throttle position sensor, but I don't know what IAC stands for. I'm looking at the ford shop manual and I'm not recognizing that acronym.

Sep 14, 2004 | 06:05 AM

02FX4Dude

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From: Waukesha, WI

IAC = Idle Air Control valve, it controls idle speed, usually a higher speed when you first start the engine. They can stick open(or closed) sometimes and cause problems.

Sep 19, 2004 | 04:13 AM

jotom

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late,
Just got back in town so I'll give it a shot this week. Thanks for the assistance.
Clem

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Sep 21, 2004 | 12:53 PM

stinkinlinkin

Freshman User

Joined: Jun 2004

Posts: 27

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From: Calgary, Alberta

Everytime I have come across a problem like this it has been my torque convertor. Just keep that in mind. But I recommend replacing the little things/ cheap things first