highway cruising misfire?

[jt1500]

hey guys so i drive my 96 k1500 w/5.7 daily to college about 120km round trip so lately its begun to somewhat misfire or stutter like a hesitation when cruising. now when you hit the throttle it clears up, cruise and back to the hesitation. now to me this sounds like an ignition/timing issue? just for kicks i changed the fuel filter tonight but havent took it out for a spin yet. and tomorrow after class ill change out the plugs, which i know should probably be changed anyways.

any ideas?

 

[SAATR]

EGR flow issue comes to mind, since it only happens during low RPM, light throttle cruising.

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[jt1500]

EGR flow issue comes to mind, since it only happens during low RPM, light throttle cruising.

Sent from my XT912 using Tapatalk

thanks for the response. how do i go about diagnosing this? might i ad i do not have a CEL yet.

 

[SCOTTYINWV]

Sounds egr related to me also.

 

[SAATR]

Unbolt it and check the pintle valve for carbon build up, and pull the tube off and check there too. If you find a lot of buildup, a small pick and some carb cleaner should take care of it for the EGR, and a coat hanger on an electric drill can get a lot out of the tube. The ports in the intake can also clog, which requires pulling the upper intake to clean the discharge port in the manifold. I don't know if the 400's will set an EGR flow code, as I don't think that they have a way of measuring flow. The only code I have seen is a pintle position code which will be thrown if the pintle gets stuck. You may have to replace the valve if you cannot clean it sufficiently.

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[someotherguy]

If fuel pressure is up to spec, then more likely an ignition issue; worn/defective parts in cap, rotor, wires or distributor gear/top bushing.

Richard

 

[jt1500]

well i changed the fuel filter and my plugs and it seems to be running a lot better.

the plugs were beyond ed...which im sure accounted for something