Maxima 98 GXE stick shift.
Well, where to start... First off I'm driving with P0325(knock sensor) pending. I can hear that the engine needs serious tune - up and 60000 miles service which now (at past 73000) is WAY overdue. Hearing all that knocking combined with significantly decreased power leads me to think that I have at least one non-firing cylinder(my old spark plugs?!). Anyway, on this background I've got two major complaints:
A: ==>>Sometimes I hear low pitched noise/but no vibration(almost always when drive) which sounds somewhere between the sound your(stick shift) engine makes when you roll downhill at lower speed gear(using your engine to break and kill your speed without using the actual brakes) - and the low pitched,but not booming noise you can hear from (almost) busted tailpipe. It happened today too and I switched to neutral while still rolling on and revved the engine a little - the noise didn't change as far as can say. The noise is often louder than the engine and of feels like it comes from outside(first couple of times I thought that yet another tractor-trailer is overtaking). I had the chance to play with it a little before it was gone and it seems that playing with the clutch and switching gears kind of breaks it off. Or was is coincidence?..Sometimes the noise suddenly comes full-force and sometimes it pops up in the background and then gradually increases to a level where I almost can't hear the engine. It freaks me out. The first time it happened I was just arriving home at low speed - I panicked and turned the engine off.
B: ==>> Probably unrelated but this whole winter when my heater works it smells like burnt old hat and when I get out of the car I can feel the smell oozing from all over with the front end strongest and a bitt less the rear.
I don't try to destroy my Maxima on purpose but for the last three years I had to go with less maintainance than I'd like to, and now I have a lot of catching up to do.
I'll entertain any idea or advice and if someone has similar experience - please share.
Thank you.