please help!

[MDblack01xj]

Hey all, thank you for taking the time to read this. I'm a noob to the jeep world. Just got a 01 sport with 159ish on the dash. Removed front sway, 2 1/2 shackles on rear trimmed front fenders, 31x10.50s. Just recently it started to make a a bad knock or tapping noise. It does NOT do it at idle. Only in drive and usually anytime I go over 1500 RPM. If I'm at a red light it does it till I slap it into neutral then goes away. I'm praying its not nothing to serious. I can't see it being a valve or anything serious being it goes away when I put it in N. Please any help would be greatly appreciated. Thank you.

 

[TwoXJS]

Does it do it if you give it gas in N? I think it could be detonation....You can try using higher grade gas for a tank or two and see if it helps. If not, next thing I'd think of would be loose flexplate to TC bolts, or possibly cracked flexplate. My brother's '89 would knock at idle and under power and it turned out to be the cracked flexplate. You could also pull and check your spark plugs for anything other than normal colors. Here's a link to a chart for reference: http://n0tch.co.uk/wordpress/wp-content/uploads/2013/06/plugs19.jpg

 

[MDblack01xj]

Thank you for the quick response. If I put it in neutral and hit the gas it does not make the noise. If I'm sitting there in drive with brake on and touch the gas it gets REALLY loud. I'm gonna check the plugs today. Thank you again.

 

[sidriptide]

is it directly related to engine speed? if it matches RPM exactly you should be looking at the transmisssion or torque convertor.
if it sounds like something external i'd look at the exhaust for a pipe that is hitting the frame somewhere or maybe even the mechaincal fan hitting the fan shroud if you have bad motor mounts.
get a flashlight and a friend to help you. take turns crawling around looking and listening for your noise while the other is in the drivers seat.
it cant be too hard to at least isolate the area it is coming from and them come back here with your new questions.....
it's not likely detonation...