4.0 running really rough

99B4000_4x4 · 05-27-2009, 11:08 PM

My truck started running really rough today and now is barely running at all. Went up to autozone and the codes said that both the O2 sensors were bad and were running lean. That code has been saying that for almost a year and the truck ran fine until now. Should I go ahead and replace the sensors or is their something else I need to check? Thanks

JunkYardRanger · 05-29-2009, 12:22 AM

check fuel pressure if ur running lean u do not have enough fuel to the motor

Randy960 · 05-31-2009, 08:35 PM

injectors, sounds similar to the problem I was having

**AllanD** · 05-31-2009, 09:29 PM

REPLACE FUEL FILTER

Test fuel pressure

Run injector cleaner.

bad injectors are about as common as honest politicians.

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bjp · 06-01-2009, 11:02 AM

Mass Airflow Sensor could also be a problem. If its dirty then the cpu gets the wrong airflow and ends up sending in the wrong fuel amount.

05-27-2009, 11:08 PM	#1
99B4000_4x4 New Member Join Date: Mar 2009 Year: 1999 Make: Mazda Model: B4000 Engine: 4.0 OHV Class: 4x4 Used For: Daily Driver/Occasional Off Roading Posts: 4 Rep Power: 0 iTrader: (0)	4.0 running really rough My truck started running really rough today and now is barely running at all. Went up to autozone and the codes said that both the O2 sensors were bad and were running lean. That code has been saying that for almost a year and the truck ran fine until now. Should I go ahead and replace the sensors or is their something else I need to check? Thanks
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05-29-2009, 12:22 AM	#2
JunkYardRanger Member Join Date: Jun 2008 Location: Orlando Fl Year: 1995 Make: Ford Model: Ranger Engine: 4.0 Class: 4x4 Extreme Used For: MUD MUD AND MORE MUD!! Posts: 209 Rep Power: 10 iTrader: (2)	check fuel pressure if ur running lean u do not have enough fuel to the motor __________________ Built Ford Tuff with Junk yard Stuff Rice Crispies ... because when you pour beer on them, they go "Snap Crackle Burb"
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05-31-2009, 08:35 PM	#3
Randy960 Member Join Date: Nov 2007 Location: Buffalo, NY Year: 1998 Make: Ford Model: Ranger Engine: 4.0 Class: 4x4 stockish Used For: Everything Posts: 182 Rep Power: 12 iTrader: (1)	injectors, sounds similar to the problem I was having __________________ '98 Ranger XLT 4.0 5spd. 4x4 -'01 Edge front end+fleetside bed swap -Multi-Colored... for now -new everything
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05-31-2009, 09:29 PM	#4
AllanD RBV Technical Advisor Join Date: Jun 2001 Location: East-Central Pennsylvania Year: 1987... sorta Make: Ford Model: Ranger Supercab Engine: '93 4.0 Class: 4x4 Used For: Roadtrip Warrior Posts: 7,168 Rep Power: 47 iTrader: (18)	REPLACE FUEL FILTER Test fuel pressure Run injector cleaner. bad injectors are about as common as honest politicians. AD __________________ Gun Control - A theory espoused by some monumentally stupid people; who claim to believe, against all logic and common sense, that a violent predator who ignores the laws prohibiting them from robbing, raping, kidnapping, torturing and killing their fellow human beings will obey a law telling them that they cannot own a gun.
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06-01-2009, 11:02 AM	#5
bjp New Member Join Date: Oct 2007 Year: 1994 Make: Ranger Model: XLT Super Cab Engine: V6 4.0L Class: 4x4 Used For: Everything Posts: 5 Rep Power: 0 iTrader: (0)	Mass Airflow Sensor could also be a problem. If its dirty then the cpu gets the wrong airflow and ends up sending in the wrong fuel amount.
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