2003 Explorer with a 4.0L has a misfire. | Ford Explorer - Ford Ranger Forums - Serious Explorations
  • Register Today It's free!

  • Holiday Special! - 2 for 1 Elite Explorer sale!

    Right now you can purchase an Elite Explorer membership for $20 and receive a two year membership!
    If you have an existing Elite membership contact me by PM and I will upgrade your account manually.

    Click Here to start your membership and get rid of the ads!

2003 Explorer with a 4.0L has a misfire.

need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
Okay, I have a 2003 explorer xls with the 4.0 v6, 140k miles. Since it rolled over 100k it has started acting up, rough idle in park, rpm dips while in gear and sometimes dies (which is really annoying and slightly embarrasing when stoped at a redlight). Also when at speeds of around 58 mph or below with the cruise on when you start going up a hill the car "jumps". Doesnt do it so bad without the cruise on because you can force a downshift causing it to stop "jumping". So far we have put 2 sets of plugs and plug wires, along with a new coil pack, nothing has helped. also a mass air flow sensor. The check engine light hasnt came on so therefore no codes have came up besides the occasional flashing of the light to indicate a missfire. Took it to a guy with a code reader and he said that untill a code came on that he couldnt pinpoint the problem.
Any ideas to what it could be would be much appreciated
thanks
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





BrooklynBay

Moderator & long time member.
Staff member
Moderator
Elite Explorer
Joined
November 11, 2005
Messages
55,880
Reaction score
946
City, State
Brooklyn, NY
Year, Model & Trim Level
88 89 93 95 96 Aerostars






swetrid

Explorer Addict
Joined
September 30, 2010
Messages
1,888
Reaction score
7
City, State
Reading Pa
Year, Model & Trim Level
1999 Eddie Bauer
If you use a ford scanner you can access mode 6 data which will show which cylinder is misfiring even without codes.
 






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
i think when they tried it last it said cylinder 3 or 4, but i figured that after two sets of plugs and wires and a new coil pack that it would be something else other than that. and it may have even been two coil packs. cant remember, my dad did all the work on it.
 






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
oh and not to mention that gas milage is horrible. i get around 15 to 16 mpg town, highway, foot in the pedal, normal driving, doesnt matter.
 






matt0248

Well-Known Member
Joined
July 12, 2010
Messages
761
Reaction score
2
City, State
Chicago
Year, Model & Trim Level
02 XLT V8
Clean the throttle body (throttle body cleaner only) and MAF (with MAF cleaner only). See if that helps. Also, double check that the plug wires are routed correctly. I cannot begine to count the number of time cars came into the shop where someone mixed up two plug wires.
 












gaw

Member
Joined
July 25, 2006
Messages
49
Reaction score
0
City, State
Fort Worth, Texas
Year, Model & Trim Level
03' XLT
Your story seems a lot like mine. I was getting misfire codes and changed the same as you have. I took it to Ford and they found an O2 sensor problem that was intermittent. They are suppose to be checked at 100K, so I figured I was performing regular maintenance. Long story short...my issue was the O2 sensor on the drivers side before the cat. I even talked to a few of my mechanic friends and they said that there was no way the O2 sensor was my causing my misfire problems. Changed the sensor and all is well. Hope this helps.
 






not8taxi

Well-Known Member
Joined
March 26, 2006
Messages
586
Reaction score
0
City, State
queens, ny
Year, Model & Trim Level
02 XLT
Your story seems a lot like mine. I was getting misfire codes and changed the same as you have. I took it to Ford and they found an O2 sensor problem that was intermittent. They are suppose to be checked at 100K, so I figured I was performing regular maintenance. Long story short...my issue was the O2 sensor on the drivers side before the cat. I even talked to a few of my mechanic friends and they said that there was no way the O2 sensor was my causing my misfire problems. Changed the sensor and all is well. Hope this helps.

did you have the cel on?
 












BrooklynBay

Moderator & long time member.
Staff member
Moderator
Elite Explorer
Joined
November 11, 2005
Messages
55,880
Reaction score
946
City, State
Brooklyn, NY
Year, Model & Trim Level
88 89 93 95 96 Aerostars






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
Your story seems a lot like mine. I was getting misfire codes and changed the same as you have. I took it to Ford and they found an O2 sensor problem that was intermittent. They are suppose to be checked at 100K, so I figured I was performing regular maintenance. Long story short...my issue was the O2 sensor on the drivers side before the cat. I even talked to a few of my mechanic friends and they said that there was no way the O2 sensor was my causing my misfire problems. Changed the sensor and all is well. Hope this helps.

did it miss sometimes, and run fine others? mine only did it sometimes, but has started here lately missing and idling bad most of the time. and it seems to take longer to start than it used to, but that could be something different causing that.
 






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
and BB, not sure on the codes, like i said my dad was doing all the work on it.
 






gaw

Member
Joined
July 25, 2006
Messages
49
Reaction score
0
City, State
Fort Worth, Texas
Year, Model & Trim Level
03' XLT
Yes...the problem was intermittent...it would run fine and then start missing...the cel light would come on...sometimes the cel would go off after the "episode" of missing....sometimes it would stay on a day or two and then go off...I would go to autozone and get the same codes every time... PO303...PO304
 






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
okay that sounds exactly like what mine is doing. is there any way to check the sensors without buying all new sensors and replacing every one? i think theres 4 total, 2 on each side infront of the cat and two after. or is it just two?
 






gaw

Member
Joined
July 25, 2006
Messages
49
Reaction score
0
City, State
Fort Worth, Texas
Year, Model & Trim Level
03' XLT
Sorry...I didn't, at the time, know it was an O2 sensor causing my problems...you can google it and there are sites that show you how to test the O2 sensor. This is where I was in the process of trying to figure out what was wrong and took it to the Ford house and they found out what was causing the problem...the O2 sensor. I then said, thanks for the information (the bad O2 sensor was on the print out sheet they gave me), and paid the 90.00 fee and then went to the auto parts store and replaced it myself. I think there are 3 sensors, if memory serves me right, driver side and passenger side before the cat and 1 behind the cat.
 






need2mud

Member
Joined
December 19, 2010
Messages
12
Reaction score
0
Year, Model & Trim Level
2003
thank you. i will probably just replace them all and just hope that fixes it. lol but it sounds like it should. i will replace them in the next few weeks and see what happens. if it doesnt fix it then ill go back to poking blindly at the problem and hoping i get lucky and find it.
i love the vehicle, just wish it was 4wd and ran right. but for my first vehicle i guess i cant complain. lol
 






gaw

Member
Joined
July 25, 2006
Messages
49
Reaction score
0
City, State
Fort Worth, Texas
Year, Model & Trim Level
03' XLT
Well...I hope the O2 sensors work for you. I did all you did plus a fuel pump before I took it to the Ford house...let us know if the sensors fix it for you...
 









Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





hnybee09

New Member
Joined
May 15, 2009
Messages
6
Reaction score
0
City, State
Drums, PA
Year, Model & Trim Level
2003 Explorer XLT
I posted on another thread as well that my 2003 Explorer XLT is having similar issues. It was fine and then 3 hours later when it was run again the service engine light was on and it seemed to be running on 5 cylinders. I took it to Autozone and they checked the codes which came up for the crank position sensor and another for a misfire in cylinder 5. I changed the CPS but it is still running terrible and still flashing a code for a misfire in cylinder 5. The plugs, wires and coil were all replaced a year ago, but i still changed the plug and no difference, we checked the coil and have spark at all 6 cylinders. My next step is that tomorrow we will be checking the compression to rule out a valve issue after that I am thinking fuel injector...any thoughts?
 






Top