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Discussion Starter #1
I have an 87 F-150 with a 300 cu. in. 6 in it. The EMIS light just came on when I was on the way back from a long trip. I removed the black battery cable to reset the computer to make sure it wasn't a fluke, and the light came right back on. What causes this light on my vehical? I just want to know before I take it to a shop and someone tries to lie to me about what is causing it.

Thanks Guys!!!


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1987 Ford F-150 100% Stock Minus the K&N Air Filer
Motor from 92' F-150 with 70000 Miles on It. 0-60 in like 18 Seconds ;-P



<font size=-1>[ This Message was edited by: MrBooMY on 1/2/02 12:45am ]</font>
 

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it's comes on some where around 70000 miles so you'll take it in to have the emis. checked there should be a switch under the dash that you use to reset it sometimes it's very hard to find it
 

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The switch mentioned earlier is a little black box, usually mounted near the steering columm area. It's about 2" x 3", rectangular in shape, with (if memory serves me correctly), 3 wires coming out of it.
There (if it hasn't been messed with before), be a little white sticker on the front of it, that says reset. There is a hole directly behind this sticker. You push a small blunt object into the hole, (you can kinda feel the contact depress), and then turn the ignition key to ON position. The light will turn off while you're pressing it. Then cycle the key again, (or start the engine), and the light should be off.
Ford put them on the older vehicles to have you come in and have your emissions inspected. (mostly egr back in those days).
Now, if memory also serves me correctly, YOUR vehicle is too new to have that box. 83-84's had them I think.
Your EEC vehicle, will pop a code when any input sensor (and one output sensor), are bad.
Give me more details on your setup, and I"ll try and brainstorm it a bit more.
 

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Most likely its the O2 sensor but it could be something else like needing new spark plugs or possibly an injector going awry.
 

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Just for the sake of 'throwing something out there', I'll say this.
For the most part, 4.9's were very prone to having EGR position sensors, (evp) going bad. Second would be sticky egr valves. Third would be sucked in throttle body gaskets, throwing lean codes, and/or unable to control base idle codes. Fourth would be 02 sensors. I could to on, and on. Without codes, and more info on vehicle, it's all guesswork/load up the shotgun.
 

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Discussion Starter #6
The truck has problems idling when I first crank it up cold. The EGR is actually disconnected because it was sticking really badly and causeing it to miss ever so often. Hope this helps in getting a Diagnosis for me, I'll try to borrow my friend's code reader.

Thanks for all the replys guys!!
 

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Easy check for the throttle body gasket, is to spray carb clean/brake kleen/WD40 around the throttle body (between body and upper intake), and see if idle increases/decreases.
Hard start, high idle, missing/buck/jerk, all problems created/seen/experienced by sucked in throttle body gasket. Cheap fix.
See gobs of secondary ignition components rotted away on these too. (ck for greenage/corrosion @ all ends of plug wires/cap, etc.
Lots and lots of things to look for.

good luck, have fun
 
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