Hi, I've been reading these forums for awhile now and they are quite informative. any help would be greatly appreciated.Just yesterday I noticed that I started to have a knock at idle up to about 3k when I can't hear it anymore(i don't think its going away, i think i can't hear because of my exhaust). The promblem is when i listen in the engine bay i can't hear the noise very well if at all. I can hear it the best when i am sitting in the car. Its pretty pronounced, but if i lean out the window i can't hear it. I don't think its the lifters because i stethoscoped the valve cover and could'nt hear anything out of the norm. I don't think its rod knock either though thats not out of the realm of possibilty. LIke i said its barley audible in the engine bay. The noise does seem to be coming from down near the alternator so it could be rod knock i guess. I don't know though i'm stumped and its really frustrating me. Also another possibilty might be a vaccum leak causing pinging, though it does'nt sound that way. Thanks and like I said any help would be great.

have you lost a significant amount of oil recently?

exhaust leak?? that will sound like knocking sometimes

I have an oil leak in the head gasket around the o-ring oil seal like a lot of 420a's, but i have not lost a significant amount of oil latley, my valve stem seals are also leaking slightly, but like i said I always maintain the oil level. Also I do have an exhaust leak around the flex pipe, I did'nt think it was significant but that could be the promblem, but I doubt it. Thanks for the tips though, i'm deffinatly gonna look into the exhaust leak possibilty, though i don't think thats the promblem.

sounds like the exact same thing i ran into just last week. it was hesitating and popping while u were trying to accelerate in low rpm's? all i did that fixed it was to replace to spark plug wires. $30 spent and made everything right as rain. i thought it wasn't going to be even half that simple to correct but it's sometimes the little things u take for granted.