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4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

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Old 12-05-2012
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Join Date: Sep 2012
Location: Buffalo , NY
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Runs rich and lean?

Hi I have a 1994 ford ranger supercab 4.0 ohv 5 spd and it is misfiring I pulled the spark plugs and the 3 spark plugs on the drivers side were white like they were being starved of fuel (lean)and the 3 plugs on the passenger side were a flat black like it wasent brining fuel compleatly (rich) so I replaced them and the same thing occurred. Idk what this could be at this point coil pack, fuel pressure regulator, o2 sensor, fuel injectors, I'm just puzzled and would like some input from other ford owners

Last edited by Rydogg311; 12-08-2012 at 05:30 PM.
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Old 12-06-2012
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Sounds like it's most likely the injectors.
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Old 12-08-2012
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Location: Buffalo , NY
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Also when I remove the MAF it seems to drive a little smother jus dosent have as much power I was also could a vacuum leak cause one side of the engine to run lean?
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Old 12-14-2012
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I'm not as well read with the OHV, but I would check for vacuum leaks as well (PCV area?). I know this has caused me problems before when my engine was missing. It wouldn't hurt to clean the MAF as well. Could just be some nastiness on the MAF causing there to be bad readings of air temp into the motor causing incorrect mixture of air/fuel.

Has your check engine light come on? If so, somebody like advance auto parts can check for DTCs via the OBD port under the dash.
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Old 02-05-2013
Join Date: Mar 2010
Location: Roy, Utah
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If it's a California Emissions truck you have a Camshaft Position Sensor at the back of the engine (a little on the driver's side of center) that controls the amount and timing of fuel sent to the injectors. It sounds like something you should look at. The Haynes manual has a test you can do that shows if it is operating correctly. Try that. Good luck.
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