I just got an 03 evo 8 about 2 weeks ago. I'm still not very familiar with it. Just today I was driving the car, I entered the freeway and for some odd reason, the RPM won't go over 4000, and once it hits 3000, I was able to hear the turbo spooling/hissing. It was loosing power. Every time I stepped on the accelerator, the turbo would make a hissing sound. The car wouldn't go over 80MPH, if I tried to push it, the car would start bogging and it felt like the transmission wasn't catching. I'm not sure if that would be a boost leak, or possibly the fuel system, but everything is stock. Could it also be that the car is going on limp mode? Any help would be great, I'd appreciate it. Thank you.

 

Almost sounds like its possible that the clutch is slipping. But I'm no expert.

 

If it was the clutch your rpms would scream but you wouldn't go any faster. Could be boost leak, I'd crank down on all the clamps and replace any bad ones. If you still have a leak it could be the throttle body leaking. Take it to get smoke tested.

 

I doubt it's the clutch since I'm still able to go about 80MPH. And the gears are still catching on. It makes a real loud spooling/hissing sound when the RPM is at around 3000-4000. Can I take it to any shop to get it tested or would it only be at turbo specialist shops? Thank you.

 

Also, would that really happen if it has a boost leak, that when I hit around 4000 RPM the car won't go any faster and start bogging down? It only happens when I'm in gear, but when at neutral and I punch the accelerator, it hits 7000 like nothing. It jus gets stuck at about 4000 and I can't gain anymore speed past 80MPH. If I try to punch it, the car starts to jerk that it almost sounds like the transmission is slipping.

 

do a boost leak check, its really easy, there is a STICKY that shows you how to make your own boost leak checker for a few dollars at home depo. All you need is an aircompressor and some simple hand tools, the whole process will only take 10 or 20 mins

 

Your car will not fully boost if your not in gear since there's no load on the engine to put serious exhaust out. Also your turbo doesn't really start putting out until around 3-4k rpms it makes sense.

 

Sounds like a boost leak to me..

 

I have the same problem, at full throttle it involuntarily opens the aftermarket HKS SSQV I have.. Even if I stay on the throttle fully open... So in higher RPMS basically it's as if I took my foot off the gas to shift... But I'm still flooring it...........

Think it's a bad valve in the BOV or something else leaking?

 

actually after repairing my car evo 7 from a minor nose cut damage, no really strange sound it seems everything is fine but, when I floor it when my speed goes and floor the gas pedal up the rpm "bogs" at around 5000rpm I think and than goes on again it just "bogs", actually I noticed that it might be an exhaust leak,

or maybe a boost leak when I changed my intercooler(not the same as stock fmic side pipes which can use a straight silicone hose) because my piping were shaped curved and the aftermarket intercooler I bought are straight so I used and 45degree elbow silicone hose to match it, every pipes and hose are t clamped.


Thank you so much dont know how to fix it.