and gain access to Reviews and Discussion of the 2016 and 2017 Ford Explorer Tech Tips, How to Articles, Off-Road Modifications and Events, Street Truck Mods and Events, and much more! Since 1996 our community has covered every aspect of the Ford Explorer, Ford Ranger and all vehicles based on this platform.

Register Today It's free! This box will disappear once registered!

Truck is running rough and backfiring.. Help!

Discussion in 'General Explorations!!' started by imq707s, October 29, 2002.

  • Searches ExplorerForum.com
    Thread Status:
    Not open for further replies.
    1. imq707s

      imq707s Active Member

      Joined:
      July 5, 2000
      Messages:
      214
      Likes Received:
      0
      Trophy Points:
      0
      City, State:
      Springfield, Missouri
      Year and Model:
      1997 Mercury Mountaineer
      I've got a 97 Mountaineer ( just like an explorer) with a 5.0 v8 and 87,000 miles. It's all stock and I have had no other problems since I've owned the truck. It has lost most of it's low end power and if you mash the gas at a stoplight it will burble and pop really loud out the exhaust before it finally starts to rev. If I'm cruising around town at around 40mph and the RPM's are really low (1300) it will somtimes backfire. I'm not getting any check engine light at all. My millage has not went down either. I'm thinking it's either plug wires, plugs, or O2 sensor. It seems like it's loading up one of the cylinders with gas, and then it fires the plug and BAM, it backfires. I put new plugs in it 10,000 miles ago, and I thought that if one of the 4 (yes that's right, 4) O2 sensors was going bad, it would trigger the check engine light. Can some of you guys give me some help. Thanks.
       
    2. Support EF


      Join the Elite Explorers for $20 a year

      Explorer Forum has probably saved you that much already, and will continue to save you money as you learn how to diagnose and fix problems yourself, and learn which modifications work without having to experiment on your own. Elite Explorer members see practically no ads, add your own profile photo, upload photo attachments directly to your posts and Media Gallery, create more private Conversations, and more. Join Today. Your support is greatly appreciated.



      to hide adverts.
    3. section525

      section525 sextion525 Staff Member Moderator Elite Explorer

      Joined:
      February 11, 2001
      Messages:
      14,786
      Likes Received:
      1
      Trophy Points:
      0
      City, State:
      Red Bluff, Ca
      Year and Model:
      1975 Ford Bronco 4x4
      Check your wires and coil packs. My '96 5.0 has had two coil packs go out on it so far. It acts sort of like what you describe. You should change your wires anyway since you have over 80k on them.
       
    4. imq707s

      imq707s Active Member

      Joined:
      July 5, 2000
      Messages:
      214
      Likes Received:
      0
      Trophy Points:
      0
      City, State:
      Springfield, Missouri
      Year and Model:
      1997 Mercury Mountaineer
      Is there any way for me to test each coil pack?
       
    5. section525

      section525 sextion525 Staff Member Moderator Elite Explorer

      Joined:
      February 11, 2001
      Messages:
      14,786
      Likes Received:
      1
      Trophy Points:
      0
      City, State:
      Red Bluff, Ca
      Year and Model:
      1975 Ford Bronco 4x4
      What I did was pull the wires off while the motor was running and make sure there was a spark coming out. Just be very careful not to get shocked!

      Go like this: pull wire number one, make sure spark is coming from the pack, put it back. pull wire number 2, etc etc.

      You can use some sort of non-conductive pliers or something.. but I just used my hands. Just dont get too close to the spark! :D
       
    6. Howard

      Howard Moderator Elite Explorer Staff Member Moderator Elite Explorer

      Joined:
      May 17, 2002
      Messages:
      4,195
      Likes Received:
      1
      Trophy Points:
      48
      City, State:
      Milton Keynes
      Year and Model:
      1998 SOHC UK SPEC
      Ok here is how to test the coil pack:

      To check the primary (which must be ok or no spark at all) disconect the plug and probe the connections with an ohm meter (three pins centre +ve both outers -ve) looking for 0.3 - 1.0 ohms.

      To check the secondary
      Probe the pairs 1-6,3-5,4-7 and 2-8 looking for 6.5k - 11.5k ohms.

      In theory you can check the plug wires with the meter looking for about 5k ohms per foot cable.

      With the milage you prob need new plugs and leads.

      Just my 2c worth anyway hope this helps.
       
    7. imq707s

      imq707s Active Member

      Joined:
      July 5, 2000
      Messages:
      214
      Likes Received:
      0
      Trophy Points:
      0
      City, State:
      Springfield, Missouri
      Year and Model:
      1997 Mercury Mountaineer
      The motor idles great, but only acts up when it get a heavy load on it. Is it possible for a coil pack to act up under heavt loads, but work great under light loads (idleing)? Thats kind of how bad plug wires act, they start to act up under heavy load.
       
    8. Howard

      Howard Moderator Elite Explorer Staff Member Moderator Elite Explorer

      Joined:
      May 17, 2002
      Messages:
      4,195
      Likes Received:
      1
      Trophy Points:
      48
      City, State:
      Milton Keynes
      Year and Model:
      1998 SOHC UK SPEC
      I'd start with new plugs and leads not too $$$$ and needed soon anyway.
       
    9. imq707s

      imq707s Active Member

      Joined:
      July 5, 2000
      Messages:
      214
      Likes Received:
      0
      Trophy Points:
      0
      City, State:
      Springfield, Missouri
      Year and Model:
      1997 Mercury Mountaineer
      Well, I finally went out and bought some new spark plug wires. I got the good Borg-Warner wires for around $60. After I put the new wires on the motor ran great. Started much easier, idles smoother, and didn't backfire when I would power brake it like before. I thought my problem was fixed. But now two weeks later, it's starting to run rough and backfire again. What the hell is going on? I'm still not getting any check engine light. I checked all the wires again and they look ok. Any suggestions?
       
    10. Alec

      Alec Elite Moderator Moderator Emeritus

      Joined:
      April 25, 2000
      Messages:
      15,997
      Likes Received:
      0
      Trophy Points:
      0
      City, State:
      Houston, Texas
      Year and Model:
      2008 JK
    Thread Status:
    Not open for further replies.

    Share This Page




    Click Here

    We Support Our Troops!