Rough running at crusing speed
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Joined: Oct 2008
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Rough running at crusing speed
My 2000 4.0litre Ranger is running real rough and is throwing code 1151 and telling me that cyclinder 4 is misfiring. I have replaced both O2 sensors before the cat. The mileage is poor now too. The truck seems to hesitate when I accelerate and bucks when I am going a steady speed, if I speed up the rough bucking stops until I am at a driving speed. I am at a loss here as to what is my next step. Any help would be greatly appreciated.
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Joined: Jan 2002
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From: suburban atlanta
I'd check 2 things: MAF and fuel pressure regulator.
If you unplug the MAF and the critter runs smooth and better, you can figure that it needs cleaning or replacement. It uses a 'default' setting if unplugged, and will throw a code. The default would be a guess, but not an outer space value thrown by a defective MAF.
The pressure regulator could be dumping too much fuel into the intake, and fouling #4. If it has a diaphragm, make sure that fuel is not getting pushed into the intake through the vacuum line... that could feed one cylinder a WHOLE lot of fuel..
tom
If you unplug the MAF and the critter runs smooth and better, you can figure that it needs cleaning or replacement. It uses a 'default' setting if unplugged, and will throw a code. The default would be a guess, but not an outer space value thrown by a defective MAF.
The pressure regulator could be dumping too much fuel into the intake, and fouling #4. If it has a diaphragm, make sure that fuel is not getting pushed into the intake through the vacuum line... that could feed one cylinder a WHOLE lot of fuel..
tom
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Joined: Nov 2008
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Mine is doing pretty much the exact same thng but with the #3 cylinder. I've been told it is mostly likely vacume hose, plugs and wires or injector. I'm changing the plugs tomorrow to see if that fixes it, if not it might have to go in to get the problem fixed
