I just bought my 2003 Evo 8 back in July and ever since it has had numerous misfire problems and is running rich. The car was used and came with a Perrin Test Pipe and CEL fix, this is the only mod on the car. The car runs fine, but every 4-6k miles I get a CEL that comes on. The last time this happened the car sputtered in power in the highway going about 70-80mph, lost power and sounded like it was in limp mode, or 50% power loss. The car has 30k miles on it.

I drove it to the dealer and say the error log says misfire and cat failure. They basically want to change the test pipe and second 02 sensor out for a new stock cat and 02 sensor for $900. They said "your car is running rich because the first and second 02 sensors dont work in conjunction properly and the cat is missing". "This is causing the ECU to make the car run rich".

From my understanding, I thought the first 02 sensor was the only one used to judge the air/fuel ratio?

What can I do? Do you guys think the Perrin CEL fix could malfunction and cause a problem like this or is the dealer giving me the run-around ?

Thanks!!!

 

bump,,

 

If you don't plan to mod, get a High flow Cat. and leave as that.

 

That was my last option. But the question is: why would this cause a misfire, the second 02 sensor?

Does it play that big a role in determining the air/fuel engine management....i really dont know what could be causing this problem.

 

What is the code?

You can't just look at the car and know its running rich with out a Wideband.

Stock Evos run rich from fac.