FreshEvoEight

hey guys, ive owned my evo 8 for almost two years now and when i first got the car it was running in the neighborhood of -20 vacuum at idle. then a couple months ago kinda out of the blue it dropped down to around -14 to -13 vacuum at idle. i just went through my entire intercooler piping sytem, replaced all clamps i could find, did a boost leek test for good measure, and replace a couple of old looking vacuum lines. i cant find where i would have a vacuum leak and i was wondering if anyone would know of any suggestions of where to look next. thanks alot guys!

Evo9_Dubai

Did you install cams recently?

FreshEvoEight

nope, no modifications or changes were done.

evo8426

iTrader: (27)

Have you checked the lines running to the EGR?

FreshEvoEight

those were the first lines i checked and they were all in good shape and where they belong

lonestarr20

Is your A/C ON when this happens

FreshEvoEight

no its showing the same regardless of the ac... Its gotta be a vacuum hose hiddin somewhere thats leaking...

asu11

iTrader: (7)

boost leak check the car

FreshEvoEight

i already have (twice) as i said in my original statement

Ev0ikon

iTrader: (18)

Do you know what cams you have? And what RPM does the car idle at?

FreshEvoEight

stock cams. and i think it idles right at 1k ill edit if im wrong once i go double check

hutch959

iTrader: (18)

compression test
if compression is low, vacuum will be low... sometimes

crritter

I had this happen to my Evo. It just started to idle low and the vacuum dropped to -14 from -20. The car also sounded like it had a cam when my car is stock. My air fuel ratio stayed at 14.7 - 15.1 while this was happening. I fixed it by disabling the EGR through the pcm, there is a write up in the how to section. Hope this helps you

asu11

iTrader: (7)

Check with another gauge. Theres probably a leak somewhere. No reason it just randomly starts pulling less vacuum.

mrm95

iTrader: (1)

It's also possible that your timing belt jumped a notch. That will throw off the vacuum. That happened to my Civic not too long ago.