idle/smell

[jsturges18]

need help! my car is acting weird! its a 1990 240sx and its having idle prooblems. the idle randomly drops down to about 400rpm then jumps right back up to normal. also the car has a rotten egg like smell coming outta the exhaust i believe. i do have a small exhasut leak but dont think tht would really be the problem unless its the cat. anyone have any ideas on whts happening here??


thanks, jeff

[speedeast]

Sounds like a blocked catalytic converter.

[jsturges18]

yea thts wht i thought also, ill have to look into tht

[speedeast]

Check your muffler too, because broken debris from the cat could have formed a block at the muffler.

[jsturges18]

ok will do thanks, so far ive been told by my local mechanic to put in higher octane gas so like 89 instead of 87 and see wht tht does first

[speedeast]

rotten egg smell is tell-tale catalytic converter.

[jsturges18]

yea im hoping i could clean it out instead of replacing it

[speedeast]

It's broken, not gunked up. You can yank your exhaust apart and hollow it out and shake out your muffler, or just replace the cat with an ebay test pipe and shake out your muffler. The honeycomb inside gets old and brittle after 20 years, and it crumbles and chunks break off and get lodged somewhere that restricts airflow.

[jsturges18]

oh ok ill try tht when i get a warm day and lose the snow on the ground

[jsturges18]

if i were to hollow out the cat will that throw a cel?