1. Welcome to Jeeps.net!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Jeep discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Jeep owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Misfire possible vacuum leak

Discussion in 'Cherokee' started by lwlambert, Aug 15, 2018.

  1. Aug 15, 2018 at 2:53 PM
    #1
    lwlambert

    lwlambert [OP] Member

    Joined:
    Jul 24, 2018
    Member:
    #2455
    Messages:
    7
    Gender:
    Male
    First Name:
    larry
    Vehicle:
    2006 grand cherrokee 4.7 liter limited
    hi guys. have a 2006 grand cherokee 4.7 liter getting codesp2320,po113,po300,po308,po068 Have replaced coil pac on 8 cylinder and all plugs seems to misfire and too rich a mixture. Having trouble locating a vacuum line diagram. Am wondering if it is that white sensor on top rioght side of the trottle body how can i test that. Any advise would begreatly appreciated. Larry.
     
  2. Aug 15, 2018 at 3:27 PM
    #2
    Prerunner1982

    Prerunner1982 Well-Known Member

    Joined:
    Aug 4, 2017
    Member:
    #1745
    Messages:
    1,356
    Gender:
    Male
    First Name:
    Jon
    Vehicle:
    93 XJ 2 door
    The white connector towards the top of the throttle body? (see picture) That is the throttle position sensor. It looks like there is a two part video on Youtube that may help with testing. I can't link to it right now as I am at work. This may be the cause of the P0068 code. Did you clear all the codes to make sure they all come back especially after changing the coil?
    [​IMG]
     
  3. Aug 17, 2018 at 11:29 AM
    #3
    Awrench

    Awrench Well-Known Member

    Joined:
    May 12, 2018
    Member:
    #2303
    Messages:
    975
    Gender:
    Male
    Vehicle:
    3 jeeps
    How is the repair going on the jeep?

    if not corrected give a update and we will reevaluate
     
  4. Aug 21, 2018 at 7:14 PM
    #4
    lwlambert

    lwlambert [OP] Member

    Joined:
    Jul 24, 2018
    Member:
    #2455
    Messages:
    7
    Gender:
    Male
    First Name:
    larry
    Vehicle:
    2006 grand cherrokee 4.7 liter limited
    ThANKS SO MUCH FOR YOUR ADVICE. i REPLACED THE map SENSOR ON THE MANIFOLD AS W ELL AS THE INTAKE SENSOR aLSO i REPLKACED THE COIL PACK FOR CYLINDER 8 AS WELL AS ALL OF THE PLUGS WITH A GAP OF 40. i DROVE IT TODAY ABOUT 15 MILES AND THE IDLE IS EXTREMELY LOW AND ALMOST MAKES THE JEEP JERK SITTING AT A TRAFFIC LIGHT . bUT IT IS NOT CHOKING DOWN. wHEN i GOT BACK HOME i CHECKED THE COMPUTER READINGS AND NOW ONLY TWO CODES ARE COMING UP. po 108 AND po 300. i WOULD GREATLY APPRECIATE ANY ADVICE. bY THE WAY, WHAT IS THE BAROMETRIC PRESSURE READING HIGH SHOWS AND DONT KNOW WHAT TO CHECK.
     
  5. Aug 21, 2018 at 7:42 PM
    #5
    lwlambert

    lwlambert [OP] Member

    Joined:
    Jul 24, 2018
    Member:
    #2455
    Messages:
    7
    Gender:
    Male
    First Name:
    larry
    Vehicle:
    2006 grand cherrokee 4.7 liter limited
    New update from lwlambert. 2006 grand cherokee 4.7 liter. I have replaced thr MAP sensor in front of manifold, the i ntake air sensor on manifold body all plugs and the coil pack on cylinder 8. I used my propane tank and hose trying to find any vacuum leak but could not find one even though it seems like ma vacuum leak. canceled the tools code readings and took it out for sbout 15 mils. It is idleing very low where when I am stopped at a traffic light it jerks as it it is going to choke down but it does not. When I got back home I now am down to two codes. PO108 and PO300. It is saying the baeometric pressure reading is high. What do i do to correct that and stumped on the multiple misfire. Any suggestions would be greatly appreated . Anyone wellcome to join in. Thanks Larry
     
  6. Aug 21, 2018 at 8:07 PM
    #6
    aggrex

    aggrex Well-Known Member

    Joined:
    Sep 12, 2016
    Member:
    #203
    Messages:
    4,832
    DE
    Vehicle:
    Backcountry '16
    Tuffy>AEV>TTO>JW>STech>EVOcage>MagnaFlow>SpiderTrax>RockHard>TF>SpringTail>67design>Bolt>GPCA>Curt>
    Great to hear you made some progress. After clearing the codes these two codes remain? The PO108 points toward the MAP sensor at fault or plug/wire connections or ECM. For PO300 go thru this mini check list: spark plugs wires, EGR valve, O2 sensor(s), CPS, fuel injector(s), cat converter(s)
     
  7. Aug 22, 2018 at 9:16 AM
    #7
    Prerunner1982

    Prerunner1982 Well-Known Member

    Joined:
    Aug 4, 2017
    Member:
    #1745
    Messages:
    1,356
    Gender:
    Male
    First Name:
    Jon
    Vehicle:
    93 XJ 2 door
    Did you clear the codes by disconnecting the battery?
    The low idle may be the computer relearning the parameters. It may/should return to normal on it's own.
     
    Last edited: Aug 24, 2018
  8. Aug 24, 2018 at 6:46 AM
    #8
    SmittyJeeper

    SmittyJeeper Well-Known Member

    Joined:
    Jun 24, 2017
    Member:
    #1601
    Messages:
    70
    Gender:
    Male
    Vehicle:
    06 wrangler 4.0 6speed
    5" lift, 4.11 gears, tru-trac limited-slips, winch, bumbers... you know the rest.
    Try cleaning the throttle body with a brush and some carb cleaner, be careful not to get to much cleaner down the intake, some is ok. Also put a vacuum gauge on the intake manifold and see if the vacuum is bouncing or holds steady. 4.7 engines are known for having the valve seats come loose and causing these codes.
     
To Top