# Vacuum Leak Symptoms



## 2FIZZLE (Jun 11, 2005)

I own a 92 240 with a KA24DE. I can't tell if I have a vacuum leak or a bad IACV. The Idle surges wether the engine is cold or hot, and after 10 min or so of driving the surging stops and it idles around 1500rpm. It's freakin' annoying so any help would be sweet.


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## dkdeleon (Jul 28, 2005)

I would check for vacuum leak.
sounds like you have small leak.


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## 2FIZZLE (Jun 11, 2005)

I've also noticed that I'm only getting about 22 mpg! How do I do a vacuum leak test?


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## rogoman (Dec 16, 2004)

2FIZZLE said:


> I've also noticed that I'm only getting about 22 mpg! How do I do a vacuum leak test?


Your bad MPG may be due to a bad O-2 sensor.

To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. A good place to connect to is the charcoal canister. There should be three hoses connecting the carbon canister. Two of the hoses go to a purge valve that's built into the canister. The second larger hose off the purge valve should be your vacuum line. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg.

If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.


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## 2FIZZLE (Jun 11, 2005)

Thanks for the info. The 02 is actually brand new.


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## scapi (May 15, 2004)

check the ground connections on the drivers side top - back of the motor. There are 2 ground connections there, one of mine was loose. Took serveral months to track down. Runs great .... now it need a new clutch???? :cheers:


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## 2FIZZLE (Jun 11, 2005)

Update:

The car now runs worse! It now only gets 250 miles per tank. The exhaust smells like fuel, and it acts like it wants to stall. i'm going to check the EGR valve and the IACV. i checked the fuel pressure and it is 40psi with the vacuum line on. So I'm thinking that the diaphram on the EGR has a tear in it.


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