5,000 rpm sputter?

[nitronick97]

Thought my car was missing at high rpm but after I've replaced a lot of common problem ignition components I'm getting stumped and tired of chasing the problem. New plugs (br6ef 30 gap for nitrous), new wires (msd 8.5mm), just put an ACDELCO opti in it last night and that didn't fix it (cleaned up the power throughout the rpm range but didn't fix the main sputter problem after 5k rpm). Put an oem fuel pump in it last spring and changed the fuel filter as well. I have run it with a fuel pressure guage and it held pressure so I don't think that's the issue.

My dad suggested it could be valve float. So I read some forums and it's a common thing on lt1 motors I guess.

If anyone has some info or if I'm leaving out anything out please let me know! The motor has never been opened up, it's only full exhaust and other bolt on parts. 97 z28 160,XXX miles

[englundjd]

It is very possible that valve float is happening, thats a lot of miles on that engine to be beating on it.

[popo8]

Is it a stock motor?

[englundjd]

@popo8 he said its never been opened up in the op

[popo8]

@popo8 he said its never been opened up in the op

Shit... my bad. it didnt "click."

[nitronick97]

@englundjd @popo8 I can't complain, it still rips and runs good for having those miles on it. Except for the whole valve float thing.... I'm considering a H/C/I/N, splyed 4 bolt setup.

[popo8]

My ta is all stock with just shy of 190k and no sputter (knock on wood). Idk much about valve float over high mileage.

Maybe Lloyd could weigh in. ..

@ NightTrain66

[englundjd]

@NightTrain66

[nitronick97]

I was going to call him today but got too busy! I just don't know what else it could be? Bad coil? MAP? MAF? I'm still learning things so any info is appreciated!

[popo8]

I guess if u got a weak spark... so maybe coil.