slob20ef

ok so when i start my ls vtec it hunts ide from 1000-1500 rpm. When i run it down the road its fine, but if you let off the gas and let it come down to 1500 it will try to hunt idle again. Just wondering what vacuum lines would cause this. I took out the black canister that runs the vacuum lines, but i know the brake booster, FPR, evap to the throttle body is hooked up, just wondering what other vacuum lines would cause this?

slob20ef

can anyone help?

Former User

Could also be a leak from the throttle body or IM gasket.

Is the CEL ON? Have you cleaned the IACV? Do you have a FITV? Is the coolant level low? Have you tried bleeding the cooling system?

slob20ef

CEL is on, but only for 02 sensor not being hooked uo
also the coolant is full and the IM and TB are tight
i have not cleaned the IACV and dont know if i have
a FITV, and i did bleed the cooling system. its a gsr head
btw. Thanks. Im almost positive its vacuum. car runs fine
when u keep it above 1500rpm

slob20ef

bump

Former User

If you cover the top of the throttle body with your hand while the engine is idling, can you kill the engine?

Try cleaning the IACV. Does the idle speed change by covering the IACV port in the throttle body with your finger?

Here's a link for the FITV.

dumpsterbaby

get a can of brake cleaner, with the engine running spray brake cleaner over any part where there may be a leak, if the engine bogs down youve found your leak

bleedblue94

it also matters if you torqued the im down in the proper sequence...

slob20ef

ok i did start the car and cover the TB Vacuum, and it did nothing. Im not even sure where to look for this vacuum, When everyone is saying clean the IACV im not even sure where it is. and the manifold is torqued in sequence to spec. Anything else guys? This hunting idle is super annoying, and it does it all the time, not just when its cold

Former User

You clearly have a massive vacuum or intake air leak. Check for any disconnected vacuum hoses. Otherwise, you may need to retorque the throttle body and IM or replace the gaskets.

Swansen

there is your answer there, alternatively you can have a shop do a smoke test, it finds vacuum leaks, and only takes like 10 minutes.

slob20ef

i know that the vacuum to the throttle body is not hooked up, and there is a vacuum from the evap unit that sits on the side of the manifold, one goes to the Secondary IAB, and i know there is suppose to be another one that comes from it, I took out the black evap canister or whatever it is, that runs all the vacuum

Former User

Have you blocked all those vacuum nozzles on the IM? If not, there's the problem.

slob20ef

no i have not, just wondering all what nozzles to block, and whats the easiest way to do it? Thanks alot guys

slob20ef

anyone?