Hello everyone, I am very confused and starting to desperate.

EVO8 2.3 stroker GTX35R , car was running great, but one day at ractrack, I used some fuel cocktail (alcohol +gas + ?), initially runing great but after some laps, car started to lose power and exhaust poping. Returned the car in a flatbed, drained all the fuel, and full revsion.

And now the car cranks, idle and normal run, fine, even can push gradually to any rpms. But the problem is when you really push the throthle to flat, engine start to accelerate, and start to rise the rpms, but suddenly, acomplete power loss, and maybe an exhaust bang. I am very concerned about it, I think it's very risky.
I dont know if that coktail damaged anything on the fuel system, or is a ignition problem.

Any suggestion is very apreciated

 

do you have a catalytic converter? maybe dead 02 sensor? check your hoses,

 

no cat, front O2 sensor replaced after that.

Today I have changed all the spark plugs, I will test again.

 

Given that you experienced a loss of power and exhaust popping after using the fuel cocktail, it's possible that the mixture may have caused damage to the fuel system or affected the ignition. It could be worth checking the fuel injectors, fuel lines, and fuel filters to ensure they are clean and functioning properly. Additionally, examining the ignition system components, such as spark plugs and ignition coils, may provide some insights.

 

Update.

Solved

The problem was loose spark plugs, so weird

 

where was it loose?
I got fake NGK plugs once, the tip melted early on a track session.

 

I removed the 4 spark plugs from the head only with my hand, maybe 1 full turn missed.

No melting, only smoke dust since the explosion blows some part over there.

Installed new ones, and problem solved.

 

Hmm ok, i'm glad that fixes your issue. I kinda doubt it beling loose is the issue. that will be snug after the coil pack is installed. I've also seen denso plugs used which is a lot shorter but somehow still works