strange idle

[dyeguy65]

my 87 supra has a strange idle. its constantly fluctuating. it will alternate between 1k rpms and 700rpms. constantly. even after the engine is at normal running temp. i didnt notice it doing that when i first got the car. any ideas?

its a 7mgte motor with a little over 123k miles.

 

[dumbo]

Codes?

 

[DBN]

just a tip... check engine light doesnt have to be on for there to be codes. good luck. looks like a 51 to me...

 

[hvyman]

vacuum leak.

 

[easternguy2005]

vacuum - carb cleaner method found mine.

 

[DBN]

vacuum leak.

that didnt even cross my mind lol. but if you dont have a leak like i didnt then check for the 51. hope it helps.

 

[enjoi.this]

Check for cracks in your acoridian pipe to start. Then see if you can see any other rubber pipes are cracked or split. Pulling in air after the AFM can cause an irregular idle.

 

[S.A. supra]

vacuum leak maybe a hose popped off or a new gasket some where. did you work on your car before this started to happen?