I will start off by saying I have 91,000 miles on my car. I am N/A, have a cai, udp, ported tb, and stock internals. My wife says she can hear detonation starting at 3500 rpm to 4000 when I floor it. I cant hear it over my exhaust, plus she has more sensitive hearing then myself. I need to know if anyone has had this problem or heard anything about someone else with the same problem. Im not really sure what to do other then keep my foot off the gas or run higher octane gas (which i'd rather not do if I dont have to.) I need a cure, Any help welcome.

ASE certified master auto technician

Detonation is pretty loud, well, at least it was loud when I heard it. You might want to monitor your A/F readings. However those guages will only read correctly if you're at WOT. Sooooo..

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~Chris
03 SRT-4

If that is all the mods you have, you might do a complete tune-up before you start digging further. If that is done, the only way this could be happening is if you octane is really low. You need to run at least 87 octane in the car(especially in summer). You could try a full tank of 93 octane and see if it goes away. It should.

You might also consider buying gas from a different place. Use a national chain gas station instead of the no name elcheapo places. Sometimes their additives are not the best or there is water in the tank etc. etc.

So if you are still knocking after all of this, you might consider mopar combustion cleaner in the intake. I think all you need is one can. Maybe you have too much carbon deposits on top of the cylinders and it is causing preignition.

Also do not forget the new PCV valve...what the hell.

Hopefully what she is hearing is NOT a rod knocking. If this is the case...only going to get worse.

97 RS(PTE SC-61, Built Long Block, Electromotive Tec 3)It's Here!

Yeah the cheap budget gas is cheap because it has passed it's "expiration date" so it gets sold for a lower price. Over time the octane on gas lower as the chemicals break down. I stick with BP/Amoco or Mobile when filling up.

Deano has it covered forthe rest.



15.9 @ 86.7mph

Injen CAI, 55mm TB, P&P Intake, Crower Cams, Hooker Header, ERT/Catco Cat, GS-T Muffler, AFX UDP, Crane Ign Amp, S-AFC

yeah i typically put Exxon/Mobile (cuz i have a gas card from them) 89 octane. sometimes if i pull up too far or whatever i'll put 93 or 87. my car likes the 93 just fine, but when i put 87 i have an erratic idle for the first day or so. i have to open the car up some to get rid of it

sucker MC

Did you have the 60,000 mile work done? Your timing could be off if you didnt get a new timing belt at 60k

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four nails four corners four riders and four horses

Have you thrown any lean codes?

Make sure you plugs are gapped at .050 and are the correct application for your car.

If you are running the 5 heat range plug(one range hotter than stock)this could be adding to your problem. I always ran 93 octane in my car even when it was normally aspirated. Using the 5 heat range never gave me any problems. I know some people have had problems when gapping them near .053 or greater.

Tell us when your fuel filter was last changed.

What plugs do you use, how many miles on them, what gap you use and how they look(dark, gray, white)?

Stay away from octane boosters!!!! unless it is race gas, which you do not need for your application.

You should data log your car or have someone do it for you. The cost for one is minimal when considering the cost of an engine.

You can tell a lot about how a car was driven and what is going on in each cylinder by its spark plugs. If any of them look different from the other, let us know the results.

Keep us posted.

97 RS(PTE SC-61, Built Long Block, Electromotive Tec 3)It's Here!