Hello, I have an 08 Jeep Wrangler automatic. I have added a K&N drop in filter, and zero ohm plug wires and a Gibson cat-back exhaust. My Jeep has a spark knock that the dealership said was normal. It knocks on take off and going up a slight grade slowly. I have tried Mopar fuel injection cleaner, non-ethanol gas, marvel mystery oil, Lucas oil gas treatment, had my computer flashed at a now closed Dodge, Jeep dealership ( same one that said it was normal). I went to a different delership and they said they could not hear any knock only my exhaust. My buddy has a code reader and the Jeep is not throwing out a code. Any Ideas???????

 

I would imagine if you had true knock it would throw an engine code the computer should attempt to retard the timing to eliminate predotonation....if you really believe it's knock, try throwing some octane boost into the tank to get rid of it, run a higher octane fuel next time you fuel up...or look for a cooler plug to run with...just some suggestions

 

Doing anything with your oil is a waste of time.

I would go back to OEM plug wires. You can also change spark plugs.

 

if the K&N was over oiled it could mess with the air sensor, i have had the same problem with my f350& my wife's mustang spray brake cleaner works good , keep us posted

 

These are not mass airflow sensor engines that are extremely likely to oil up from the filter.

I'd go back with the stock ignition and see how it does. Having less resistance in the ignition just strains the coil and it might just be breaking down or something. Or it is allowing the spark to occur just fast enough to knock and the computer keeps trying to back it out.

 

I have one as well, as with your dealer, mine said it was normal, and due to the low quality of 87 octane.

 

If he's tried non-ethanol 87 then that 3.8L should have run like a champ. We have piss-poor fuel here and I've never pinged.

 

I'm sorry, true engine knock, or predotonation is not normal and in some instances can be extremely damaging to an engine...to blame poor quality 87 octane is a bit of a cop out in my opinion, I run nothing BUT 87 octane...I agree with the others, if it's true engine knock then I would certainly go back to stock plug wires

 

thanks didn't know (newbe ) my 09 4d torque converter Locke's and unlock at the thought of grade, normal ?

 

I have pinging too. Mine's an 09 6 speed 2 door Rubicon. The difference is that I'm running a Superchips Flashpaq tune.

With the 93 octane tune and 93 octane gas it pinged like hell and you could feel the engine lagging as the computer retarded the timing. Dropped to the 91 octane tune and it was OK.

Running the 87 octane tune with 87 octane gas there is some pinging. I've tried differnet brands of gas and they all do it. Right now it has 89 octane in the tank and doesn't ping.

My next step is to go back to stock with 87 and see if it does it.