Hi,

Haven't posted much for quite awhile, but I've been driving my Evo VIII for 88K miles or so. I was on stock clutch till ~75K or so too.

Anyway, lately I've noticed sluggishness between 3-4 K rpm, and suspected a boost leak. I popped the hood at idle and I can hear fairly loud hissing which seems to be coming from near the firewall in the center of the engine. I kind of thought it was emanating from the hose on my PVC side DIY catch can, but would that hiss at idle and leak boost? I wouldn't think so since some peeps just bought a filter on there...

Maybe it's coming from the TB?

Strangely, I'm getting pretty good gas mileage, which I wouldn't expect. I can finally get more than 250 miles out of a tank, lol.

Then again, maybe it always made that noise and the perf is just due to the heat? Any thoughts?

<edit>
Now, I'm thinking it's the FPR line where I teed for the boost gauge. If that were torn, could someone please enlighten me on the "symptoms"? Now that I think about it, my Walbro has been whining louder lately, does that all tie together? TIA!
</edit>

Thanks,

FB

 

you might wanna look 4 a vaccum leak, you would hear that at idle and thats a hissing sound and would make your car run slugish

 

I have the Ported Buschur TB and it kinda hisses but I doubt the factory TB would.

 

Thanks guys, I tightened down the tee connections where my boost gauge hooks in. The one that I think got it was the vacuum line from the next to the FPR where it hooks into the intake manifold. I replaced it and hissing was greatly reduced and car spools much better. Wow, I like this car again!

I should go through and replace as many vacuum lines as possible, car is ~5 years old!

Take care,

FB

 

you might want to check some of the vacume lines behind the intake manifold on the bottom they tend to come off i had one for about a month and did not even know it zip tie those bad boys.

 

Could also be your throttle shaft seals.