Very Rough Idle just started today! HELP!

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Dec 14, 2005 | 04:31 PM

treading

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Joined: May 2005

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From: Apopka Florida

Very Rough Idle just started today! HELP!

I have the 5.8 EFI and it has been running fine 162K on the engine. Tonight when I started the engine it ran very rough, almost sounded like a funny car at low idle. I just put new plugs, wires and, cap and rotor in a few months ago. A friend at work said it sounds like the choke is stuck shut as he could smell how rich the exhaust smelled. I didn't think the EFI had a choke. I drove it home but I had to shift from drive into neutral to keep the rpms high enough so it wouldn't die on me. Anyone with any help I would sure appreciate it.

Dec 14, 2005 | 07:53 PM

FTE Herman

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What year is your application? I'm not too familiar with the not sequential point fuel injection stuff.

If you application uses an Idle Air Control valve, that is a common cause of a poor idle.

Dec 14, 2005 | 08:49 PM

TigerDan

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Joined: May 2004

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From: The hills of No. Calif.

Is your CEL (Check Engine Light) on? The first thing to do is to check the codes. They are stored in the computer even though the CEL is not always triggered by them.

There are a number of ways to check them. A code scanner can be purchased for about 30 bucks, or some auto parts stores can check them for you, usually for free since they hope to get your business buying the needed parts. Also, you can check them yourself with an analog multi-meter, and there are other methods that use a jumper wire. Here's a page that explains how to do it:

http://fordfuelinjection.com/?p=13

Here's a page on the IAC that hkiefus mentioned, and how to test it:

http://fordfuelinjection.com/index.php?p=39

There are several things it could be, pulling the codes is always the best place to start.

Dec 15, 2005 | 09:45 AM

Kemicalburns

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Joined: Jul 2002

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From: Bend,OR

definatly check for codes. also check your oil and smell the dipstick for fuel. if you smell fuel you probably have a bad FPR. also what kinda plugs did you use?

Dec 20, 2005 | 09:37 AM

jack048307

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hey I have ran into this before the map sensor is going bad to check it with out buying anything pull the vacuum line off and plug it. start it up and see if that made a difference if so thats the problem

Dec 20, 2005 | 09:03 PM

triplepower

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I think I'm having the same problem, on my 91 250 w a 351. Not to sound stupid but where is the map sensor located? And what line should be pulled? Sorry to but in on the thread

Dec 21, 2005 | 07:58 AM

jack048307

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The map sensor is located just to the right of the heater box on the firewall. It is a three wire sensor and has a vacuum line on it. There is only one line on it.