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I have a Ram 2018 Promaster city van I bought brand new with zero miles. At around 4000 miles the van's engine light turned on so I took I to the dealership and they replaced the MAP sensor. At 4500 miles one morning the van would not start to I took it to the dealership and they replaced a fuel line. When the van came back I noticed it now was running differently.. I could hear a faint spark knock detonation.. the sound of very light back firing when I would let go of the gas under load at 30mph +. I then noticed the van was low 2 quarts so I took back to the dealer to report the issue and get an oil change( synthetic 10-20w) The dealership performed an oil consumption test and after 1000 miles the van showed no sign of consuming oil, but still had detonation spark knock. The dealer said it could not hear it. I switched to super unleaded and the spark knock improved, but I have no plan to pay $10 each time for super unleaded. I noticed my tail pipe had a very thick black soot inside - i took pictures and cleaned it. I removed my air filter, it was dirty for 6k miles, I cleaned it and noticed a big improvement in how the van was running. Planning to upgrade to a K&N washable air filter in the next few days. I just pulled all 4 spark plugs to look at them. Not sure if they are okay? I plan to take it back to the dealership to check the timing and to possibly start a lemon law process though anticipate to having to fight with them and i need a car badly now. What could this be? Are my plugs good? Worth it to change them or fight to have dealer change them?

There is a video on youtube "NoSunBeach Tigershark spark knock"

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    Take it to a different dealer, they are idiots. – Moab Jan 27 at 14:42
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    @trondhansen - Not sure where you're seeing as running lean ... those spark plugs don't look bad, other than a few deposits. If running lean, I'd expect them to be a LOT whiter than they are and not the apparent tan color (except maybe the third plug) they are. If it were running lean, you'd not see the amount of soot at the tail pipe as you are seeing. You might see it if it was running a false lean, but then you'd not get the knock occurring (fat fuel kills knock). This is a very strange situation. I agree with Moab ... take it to a different dealership. – Pᴀᴜʟsᴛᴇʀ2 Jan 27 at 20:10
  • @Pᴀᴜʟsᴛᴇʀ2 sorry my comment came out wrong,i ment to say spark plugs looks ok but if the engine runs lean it might be the cause for the knocking,ignition timing might be an other cause for the knocking and the knocking sensor will confirm the knocking in the diagnostic tool.and i agree in taking the car to an other shop to solve the problem. – trond hansen Jan 28 at 6:21
  • On additional thought on this. I did intsall a bigger battery on my 4 cylinder van (i went from 70AH OEM Led Acid to 115AH marine deep cycle) around time i noticed the slight detonation/spark knock at around 20mph to 40mph. it's very slight. My alternator is 160Amps. Not really sure it's related. I noticed it does not do it with super unleaded. – Hell.Bent Apr 14 at 19:16

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