Injector #3 Malfunction

[EclipseGST]

95 Eagle Talon AWD 5spd.

Everything on the car is basically stock. Only upgrades done are:

Evo III 16g
Comp 101200 cams
3" exhaust
Walbro 255 pump
ACT 2600

I have boost set at w/g pressure which has come to about 6-7psi.

There is no check engine light, randomly I get the P0303 which is cylinder 3 misfire.

In return, the causes for that code include:

* Faulty spark plug or wire
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector
* Burned exhaust valve
* Faulty catalytic converter(s)
* Running out of fuel
* Poor compression
* Defective computer

So my first thought was replace the plugs and wires which I did, still misfires.

I replaced the Coil pack next, still misfires.

I replaced the FPR, still misfires.

I replaced the Injector box on the firewall, still misfires.

Threw AEM EMS in it, still misfires.

Replaced all injectors with FIC 850s, still misfires.

I dont have a catalytic converter but I've never heard of this causing a misfire.

O2 sensor is good.

Compression is 175-180 across the board.

Now this misfire is interesting, it only starts to misfire when I hit 7000rpm. Anytime before that it runs fine. But when I hit 7k, the misfire starts and it feels like I completely lose a cylinder.

If I put the car in neutral or push the clutch in and hold the throttle wide open, it takes about 10 seconds to clear out and it will rev just fine with no misfire until I bring it back up to 7k rpms.

The misfire is ONLY on #3 cylinder. I can swap plugs and injectors and wires and it still does it only on #3.

The other night I rev'd it up to redline until it started misfiring and went under the hood. You can hear/feel every injector firing EXCEPT #3.

So now I'm stumped. This was before and after I changed all that I changed out.

Anyone have any ideas? This is starting to drive me insane.

I raised the rev limiter in the EMS and it still does it right at 7k.

[2bar1g]

Sounds like the injector clip or wiring to it is bad. I would check that to see if its melted/corroded/wires touching and whatnot.

[EclipseGST]

The clip is fine, I've checked that out to, I've moved all the wiring, around just havent opened up the harness yet.

What I dont understand is why only at 7k rpms.

Not 6k, not 6500, not even 6900, just when it hits 7k.

I'll rip into the harness sometime in the next few days. I really want this over with.

[EclipseGST]

Another thought I had would be cam sensor. But I would think that would kill all the injectors, not just one.

Either that or a bad ground somewhere?

And if the wiring was bad, why would it clear up after it happens?

[123abc]

Have you tried messing with the plug gaps? Probably have, just a thought.

[EclipseGST]

100% positive its not the plugs.

I'll look into missing grounds and rip the wiring harness apart in the next couple days. The car runs just fine unless I red line it. Thats what has me stumped.

If anyone else has any ideas I'd be all for them...

[HiImBrian]

Originally Posted by EclipseGST

If anyone else has any ideas I'd be all for them...

Don't redline the car

[EclipseGST]

I'm not... I cant even get it there. Redline is 7500!

[HiImBrian]

Originally Posted by EclipseGST

The car runs just fine unless I red line it.

I'm just kiddin jakey. Maybe you should give up and buy my car. Wanna buy my ecu and try that?!