High RPM miss fire
 

any idea what it could be guys? its a head/cam LT1. could the stock fuel pump just not have enough to feed it?

Pull a plug and check it. If it doesn't have the light brown haze on it you are leaning out.

would that cause it to break up in high rpms though? almost like the power cuts out and then comes back in

is it tuned?

yes

So does it have a mis, or is it cutting out? Also howh high in to the RPMs are you when this mis/cutout occurs?

If it's actually cutting out then I'd guess first that you might be bounching off thr rev limiter. A miss could be a weak coil or Opti, even the gap on the plugs.

A stock FP will handle near 400 HP without a problem, if it's in good shape.

feels like its cutting out to me, Ron said it feels like a miss. its over 4k but def not the rev limiter. the car should be putting near 400 to the wheels

The way to know if its your fuel would be first to put a gauge on it, tape it to the windshield, and drive it...watch for a drop in fuel pressure when your "miss" occurs. second, a datalog at high RPM couldnt hurt...you would be able to see injector pulse width and see if they are static at your "miss" and beyond. If you have means of doing so, let me know and I'll dig up the formula for injector duty cycle for you.

Sounds like a coil to me.

Here you go.. with an online calc to figure it out. ;)

http://www.injector-rehab.com/kbse/idc.htm

id say its in between a miss and it cutting out. its not violently bucking, but its definately noticeable in the upper rpm range 4500+

Borrow a coil and throw it on there. And your not getting any opti death alerts are you?

no it runs fine other then that, the car is almost back together so well see how it is with the new fuel pump in it... now if only i could get a real day off lol

And of course, its always a perfect excuse to get a new MSD or likewise coil.

id say go entire MSD ignition on the car. are you running nitrous? what are the gap on the plugs?

MSD opti is iffy in its price tag being worth it. But spark plug wires, coil and 6AL are all good stuff.

I'd remove and inspect each plug wire, chances are you'll find one that got too close to the header primary and got toasted.

I'd vote opti but without experiencing it no way to be sure. opti's an expensive guess.

well the car is back on the road with the new fuel pump in and it seems to be fixed as far as cutting out. there just seems to be a slight break up up top now and i think its tuning because it smells so mad like fuel that its burning my eyes. time for a 58mm TB, AFPR and a dyno tune