check engine light

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Jun 27, 2004 | 10:43 PM

alcooner

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From: al

check engine light

I have a 1994 Ford F150 V6 300 and the check engine light came on about 3 months ago. The light stays on for a while and the truck drives rough and black smoke comes out. Had a diagnostic test and it still wouldn't pull a code. I have replace the distributor cap, rotor button, Autolite spark plugs/wires. Light went out and drove good for a week. I have check the resistance and volts on the O2, MAP, TPS, & EGR to best of my ability with a volt meter according to Haynes manual. Can someone give me any suggestions of what may be causing the problem?
Thanks,
alcooner

Jun 27, 2004 | 10:47 PM

95 F150

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It's definately a rich condition, I would pull the O2 sensor and see if it's sooted up real bad. If I had to guess I'd say the O2 sensor is your problem.

Jun 27, 2004 | 11:24 PM

acerockola77

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From: WA

If the CEL is on, it will throw a code one way or the other. Did you do both diagnostic checks? Check out this site: http://www.broncodata.com/tech/codes.htm I'd try and find that before I started throwing money at it, but I do agree with 95 F150.

Jun 27, 2004 | 11:50 PM

jim's78

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I agree with 95 f150 but if that was the problem it should have had a trouble code. I have seen the symptoms you have when the fuel pressure regulator goes bad and you get way too much pressure because the computer can't control the it anymore.
A simple check will tell you and if you have a service manual it should guide you through it.

Jun 27, 2004 | 11:55 PM

drewcoolness99

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From: TEXAS!!!!!!!!!!!!

v6? or I6?

Jun 28, 2004 | 08:41 AM

alcooner

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From: al

Thanks this thing has given me headachs, I will try the test and any other advice. I will let you all know about results. Also I forgot to put truck has 214,000 miles but does not use a drop of oil. I keep maintinance up the best I can.
Thanks
alcooner

Jun 28, 2004 | 09:32 AM

HardScrabble

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Check your MAP sensor with a vacuum pump, the resistance/voltage must change as the vacuum changes.

Run the KOEO/KOER. Use the search function here in this forum.