1993 300zx 2+2 in DC

Washington DZ · May 8th, 2008, 09:30 PM

Nissan GURU's I need your advice. My Z runs rough at a low idol speed. It gives a knock and sounds like a metal on metal knock toward the front of the engine. The sound goes away at higher rpms. I always change the oil regularly and the timing belt was done at 90k. I have 150k on the car right now. I had a shop change the belts about a year ago. The sound had been going on for two years and this is a daily driver. I ran 2 cycles of BG's fuel treatment though it. I then changed the fuel filter. It seems to be running better but the sound still persists. I was wondering if anyone knows what this sound could be and see what kind of similar issues people have had. -Washington DZ

**Spongerider** · May 9th, 2008, 12:12 PM

Quote:

Originally Posted by Washington DZ

Nissan GURU's I need your advice. My Z runs rough at a low idol speed. It gives a knock and sounds like a metal on metal knock toward the front of the engine. The sound goes away at higher rpms. I always change the oil regularly and the timing belt was done at 90k. I have 150k on the car right now. I had a shop change the belts about a year ago. The sound had been going on for two years and this is a daily driver. I ran 2 cycles of BG's fuel treatment though it. I then changed the fuel filter. It seems to be running better but the sound still persists. I was wondering if anyone knows what this sound could be and see what kind of similar issues people have had. -Washington DZ

Is it a lifter tap? If not change to a thicker oil 20w-50 and if it doesn't disappear do a compression check.