sherman943

Sorry, i'm new so I have no clue where to be posting this but anyway . . . .
I have a 97 vortec 454. When cold it starts and runs good, but after it is warmed up it will idle rough. Also when cruising at highway speeds it will shudder or buck every once and a while. Plugs and wires seem good. No vacuum leaks that I can find, changed pcv valve, and fuel filter. Not throwing any codes or check engine light. Confused, not real sure what to do here.
Thanks, Shayne

BullyDawg

how many miles does it have? i had a the same issue with mine and i discovered it was a bad fuel pressure regulator and my injectors were worn out. the best thing is the injectors can be replaced individual instead of a whole assembly.

sherman943

about 130,000 miles. It just confuses the hell out of me because it is new enought that this **** SHOULD (i know, they never work like they are supposed too) turn on the service engine light and throw some kind of code

nkh34

Is it missing or just running rough. Check your fuel pressure it might be a fuel pump. i didnt get codes either time mine went out and it drove me crazy id just be driving and it would start to run awful bucking and loosing power then catch up in a while. and if it has 130,xxx and you havent done a new pump it is very possible that your problem. if its just flat out missing though it will be a little trickier

sherman943

It doesn't seem to be missing but definately running rough AFTER it is warm. I can hear the fuel pump and it sounds normal but I guess that doesn't mean a whole lot. When it's cold it runs nice, idles good.

udiduck

Hello I'm lost as well it idles rough an cuts out when under a load it's a 5 speed so every gear before u shift has a new distributor, plugs,wires,cap,coil I put fuel pressure gauge on it for a few minutes it holds 48 psi one day it will run decent next day horrible I've been pouring sea foam in th gas no difference about to give up anybody have any ideas an can u check injectors

James Lee

i have the same thing it is the mass air flow sacer

Ashley Roach

I'm wondering what bolt one or things to do besides be exaust to get a bit more jam out of my 97' cheve Silverado K 2500 with 454 vortec. I want to keep away from internal stuff . I bought a jet tuner which was recommended by a friend and it screwed my engine , so I'm going with another same motor . It has an MSD racing coil, ignition box but box is unhooked, I'm told it blows put spark plugs , and truck has nice exaust . Looking for some good pointers and advice of couple things I could do with small things or bolt one, thanks..

Rednucleus

Welcome Ashley. You will get more responses if you start a new topic for discussion vs jumping on one that's almost 9 years old

Blayne6554

My truck did the same thing for a while and when I was told to replace my water temp sensors I didn't think it would work but it did and I also replaced my coil pack also and rebuilt the distributor but the problem was fixed with the water temp sensors and it also fixed my long crank to start problem also