question about idle

start this morning, just about to my working place, my car just start idle really bad like 0-1000rpm… almost everytime i put the gear to n, the engine just stall…sometime just go to 100 and go back to 900 and 200 and 600rpm …
on the way i back home is still the same… but just about 10 min b4 i got to home the car just runs like normal… i had this issue like a year ago. but after i did a tune up, this issue just gone

any idea??
btw, its a stock 92’ 240sx 5spd

my 240 did the same thing. turned out to be a burnt valve. or it could be this as well:

thx… did u try to use the cleaner??
and which valve ?

ive never tried that cleaner thing, i sold my 240 before i knew about this link. the guy who bought my 240 later on found the valve problem.

Great post…No info about car or engine. :axe: :axe: :axe: :axe:

i used the intake cleaner thing … spent about 3/4 can. just works for a couple day… now the idle still …

If I recall correctly one of my buddies got something that burns really hot to clean out all the ingectors and remove most of the carbon that builds inside the cylenders…I wish I rembered what it was called

seafoam