I feel my 00TL-P lose something like 20whp(big diff).the only problem (I know)is the gasket between the header and the cat which is leaking.does it really makes that difference?or something else?Oh yeah,because of very high gas price I just started to use 91 octen fuel instead of 94,it's shouldn't kill the performance,right??

 

all i know is that our cars require 91 or better...and from past threads i know there is not much diff betwen 91 and 94.... i used to use 94 all up until i found out about that, and i switched to 91 and the car performs the same... but get more opinions

 

"Feeling" a horsepower loss is somewhat of a broad statement. The only way to truly tell if you have a power loss is by putting your car on a dyno. With that said, have you kept up to date on all your maintenance/tuneup activities (ie. plugs, air filter, fuel filter, etc.)

 

How do you know you have a leak between the downpipe and the cat. If that gasket is caught between the two flanges and then tightened down, that would be a big leak. Did you install new headers? I used a small piece of scotch tape to hold the gasket in while tightening the two flanges. The scotch tape will burn off.

 

our car it is not a big deal if u put 91 or 94, but i am dare to say when u have the STi or EVO

 

The gay from muffler shop told me when they installed the CT axle-back,but i thought they B.S.and yes the headers is few months old.

 

I know I know,that's why (I think)it is the gasket problem.thanks

 

If you got the headers installed somewhere, take the car back and tell them there is a leak. If you want to do it yourself buy some ramps and a torch(maybe needed) and a long 17 mm wrench. and some wd-40

 

oops just realized 14 mm wrench is what is needed

 

If there's a leak, the OBDII will try to protect the engine by running rich, which could cause a loss of power.

When I had a leak after installing my headers, my car went into protection mode. A Geo Metro would've taken me out at the time because my car was so slow.

 

Check your Intake Bypass Valve actuator, when mine stop working I definitely lost a good amount of power.

 

Only the Type-S model has it. He has a 2000 TL-P.

 

Just realized he has a TL-P too

 

isn't the check eninge will on if it is into protection mode?

 

Yeah, in my case, the MIL came on.

But the PCM could still compensate without triggering the MIL if the leak isn't too bad, but still cause a power decrease.

 

sorry, but when I first read the, I kept thinking maybe you removed a VTEC sticker and lost all those extra sticker HP.

Anyways, yeah it sounds like the engine going into protection mode. good luck with the prob.