So my car has been acting really crazy for the past few days and I can't seem to figure it out. When I'm in 3rd-4th-5th gear and at full throttle between 4000 and 4800 rpms my car feels like it has an immediate loss of power for a half second and then just ignites and takes off like a bat out of hell!

"What is that?" I yelled the first time it happened. The passenger was confused. My friend driving behind me in his Supra called me and said I shot a 3 ft. flame out of my exhaust and the car just bound forward.......

What would cause this? I have just checked the spark plugs and they are perfect.
No carbon present.....

What is going on here?

 

Still could be sparks - look for tiny cracks in the porcelain. Check the wires?

Simple stuff first.

 

I dont see a tune in your list of mods, so what you are experencing is called fuel cut. Get a tune before you blow your motor.

 

yea that 3 1/2 exhaust is a lil too big for the mods u have and with no tune get a tune and u should be good

 

As well as the tune also check the spark plug gaps. I just had an issue with my Evo misfiring too. I changed the plugs and gapped them to .026in (EVO 8 recommended), problem solved. The old plugs I pulled out were gapped at .033-.039in. I think the Evo 9 gaps should be different but I'm sure it says somewhere on here what they should be. Good luck.

 

OP, you are in need of a tune like the others have suggested.

I would be more than happy to answer any of your questions or anyone else's.

You can pm me here or contact me on AIM (mellontuning).

Thanks

 

WAY over-kill. What made you get that?

 

sounds like ignition break-up

there is no way you would be cutting fuel halfway through your rpms, especially w/ your mods, unless your maps were seriously messed up.

inspect your entire ignition system starting w/ the primary.

to the guy that said 3 1/2 exhaust is too big....HA. HA. HAAAA!!!

 

You know the only reason I didn't say this before is because of the huge flame, but usually when a car stumbles in that range it due to knock.
I haven't heard of cars flaming after knocking though, but I don't know anyone running 3.5" exhaust.

Does anyone else think it could be knock, knock, knocking...

 

I've checked the entire ignition and all grounds today at work. No cracks in the wires, coils, or plugs. The gap is correct according to a recently former Mitsu tech that works for me. I realize I need a tune but this has only started recently and I have had this exhaust on for over six months now. I've heard knock before in evos and other cars. That's definitely not happening.

This is a feeling like all of the rotating mass inside the engine pauses for one brief time and then comes to life.

Oh....and for the exhaust....that's on there for things to come. 500+ hp out of that will sound great, and besides, you can't get away with oversized exhaust on an N/A car. This car runs insanely rich, after 2800 rpms it goes off the scale.

I have had this car run through with a fine-tooth comb for the past week trying to find the cause. I was hoping someone else on here has seen a similar concern.

 

Any codes?

 

fuel got dumped into exhaust and ignited. in rally, they do that to keep the turbo spinning. yours, however, is not rally. i also vote tune!

 

I'm not talking about rod knock, I'm talking premature detonation. Knock will cause hesitation in the RMP range, usually around peak torque (in the rpm range your talking about). I wouldn't be surprised if that is the loss in power your talking about.
Do you have a boost gauge?
Do you know what psi your running? Or spiking too?

 

r u running a test pipe or cat? could possibly be a clogged cat. maybe fuel cut. thats a maybe but i dont see that being the problem with the mods u listed.check if ur throwing a code. a tune would be nice but might not fix the problem.

 

This would tell me the gap is too wide. Stock gap is good for about 19 psi of boost, tapered.

Just throw some copper 8's in there gapped to 0.023 to confirm it's not the case, cheap and easy to do.



I had same problem, car has good power throughout gear except for a fraction of a second pause, but it regains good power... thats missfire from too wide gap or coil problems dude. Detonation would cause a drastic drop in power, not a quick gap in combustion