98cobraguy

Hi, I have 1998 cobra and I notice a slight knock between 2000-3000 rpm and it runs good and everything but I still hear a knock at those rpms and if you could help me determine what it maybe it would be greatly appreciated, thanks

97targa

sounds like a sticking valve. Put some lucas in your gas or Seafoam. You can try seafoam directly through your PCV valve for immediate results. I hope this is your problem!

98cobraguy

well I bought it saturday but I was listining to it and it does sound like its coming from the drivers side valve cover but everybody thinks its a rod

02WhiteGTVert

Your car doesn't have pushrods. Like he said,sticking valve. What fuel are you running it? Run 93 and see if that helps,if it's possibledetonation.run the seafoam through it,you'll be surprised. Hope this helps.

98cobraguy

I just bought it and put about 3 gallons of 93 in it but it still does it

bigmoose15

i have an '01 and i have the same problem. It only does it when its cold though. once it warms up i can't hear it. how would engine temp affect this?

98cobraguy

Well mine sounds like its coming from the drivers side valve cover

sstang

I get a light rattling in the exact same rpm's. Do you have an aftermarkettuner on your car? Mine came from my SCT. It doesn'tdetonate when the stock tune is loaded.I just backed off the timing a bit in those rpm's, and I also changed the a/f to slightly more richer. This fixed the problem for me. A dyno tune probably would have fixed it as well.

98cobraguy

I think im going to take out the oil filter and cut it in half to see if there is metal shavings, cause if there is it has to be a bearing or something major, if not i'll try the seafoam and see what happens