Spark Plugs? Coils? Something else? Halp!

Discussion in 'Renegade Stock Tech' started by ThatGreenJeep, Jan 29, 2020.

  1. ThatGreenJeep

    ThatGreenJeep New Member

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    Hey there,

    I'm the new kid here. I have a 2017 Lattitude with 47,500ish miles on it. I've had some sputtering going on mainly when in idle, basically misfiring. There has never been a check engine light on. I have heard and read that it might be my spark plugs? It might be the coils? I might need a tune up? I took it to a local shop and they hooked it up to the computer and drove it around and felt the sputtering but nothing showed up. Anyone have any tips or ideas for me? I took it to the dealership and they wanted an arm and a leg just to do a diagnostic!
     
  2. djthumper

    djthumper Member

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    You can try removing one wire at a time to see if there is no change. From there you can test the coil or plug.
     
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  3. zuke

    zuke Active Member

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    Honestly, rough running with no MIL (Check engine light) sounds more like a fuel problem than an ignition problem, the first thing I'd try is running a few tanks of good quality gasoline through it to see if that helps.

    Good quality gas doesn't necessarily mean expensive brands, with today's Ethanol fuels, it means "Fresh", buy your gas from a place that sells A LOT of gas, and you see the big tankers coming in every few days to fill the tanks, a tier 2 provider, like Sheetz would be fine, just so it's fresh.

    Go up one octane rating from what you normally run, just for a tank or two to see the results.

    Changed your Air Filter lately?

    Check your PCV Valve;



    Look at your throttle body for cleanliness.

    Consider a good fuel system cleaning if all the above doesn't help. I like to use BG Products for that, but there are lots of options, and if you get to that point you could ask about that here, and I'm sure you'll get some good advice.
     
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  4. ThatGreenJeep

    ThatGreenJeep New Member

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    Thanks y'all. I have taken now to 3 different places that have hooked it up with NO check engine light therefore, no codes are given. It's so frustrating! Each place has told me that it's misfiring and could be the engine coil(s) or spark plugs but unable to see which one due to no codes. I tried switching gas a while ago when this started happening and it hasn't helped. As for removing one wire at at time, do I do that while the engine is running? Is anything going to happen if I do this while the car is on?

    Thanks again y'all!
     
  5. PlatinumCore16

    PlatinumCore16 Member

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    I would agree with gas to start with. What engine is it and what gas are you putting in it, specifically the octane rating (85, 87, 89, 91, 93 depending on where you are located)?
     
  6. zuke

    zuke Active Member

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    You don't have Plug Wires, both 1.4 and 2.4 Renegades are coil on plug setups, so you can't "pull wires" to check how it runs, If you could though, you'd do it while it was running.

    Honestly, if you had a consistent misfire at the plugs, you would have a check engine light and codes.

    If you really believe this is an Ignition problem, Pull all the plugs out, lay them on a clean surface in the order they are in the cylinders, take a picture of them and post it here...

    Also look here for how to 'read' the spark plugs;
    https://ngksparkplugs.com/en/resources/read-spark-plug

    One other simple thing to check, How's your battery? A marginal battery can cause all kinds of strange behaviors on modern vehicles..

    If you want to take it to a shop, Find out who the best actual Jeep Dealer service department around you is, take it to them, and tell them it runs rough, You'll hear lots of people bitch about dealerships, but when it comes to diagnosing a problem with a vehicle, the dealer is going to have more experience than any independent shop. Don't tell them it misfires, let them figure it out.

    When you go into an independent shop and tell them "My Jeep is misfiring" you've already biased what they are going to come up with as a result.

    I almost never take my vehicles to a shop, but when I do, I tell them symptoms, and let them draw conclusions, that's what I'm paying for!
     
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  7. Dgr401

    Dgr401 Well-Known Member

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  8. ThatGreenJeep

    ThatGreenJeep New Member

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    Thanks to everyone! I took it again to the dealership that offered a "complimentary diagnostic test" but still wanted to charge me $130!
    Long story short, my mechanic fixed it for me for under $100! It needed a new coil and he went ahead and replaced the spark plug too! Yay! Now we don't feel like we will be shooting into space anymore!
     
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  9. zuke

    zuke Active Member

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    So glad you got it fixed, and genuinely surprised the computer never detected the misfire! Big Kudos to the mechanic who figured it out with no diagnostic codes, Keep that guy around!
     
  10. ThatGreenJeep

    ThatGreenJeep New Member

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    Thank you!!! My guy before he could read the code said that he thought it was the coil. The light finally came on and he plugged it up and said "Yep! I was right" hahahaha thank god for this honest man!
     
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