cruising issue, kind of like a violent hiccup, 96 silverado

[atrainsgt]

Hey everyone, first of all this is my first post, but I've been reading this forum for quite a while before I signed up. Anyway this is my 96 silverado 5.7, automatic that I've been fixing up little by little. It was in pretty rough shape when I got it. The issue I'm having now is that while cruising or under light acceleration typically above 45mph every once in a while the truck will violently jerk, just once then continue cruising smooth for a few minutes then do it again. At first I thought the Trans might be jumping out of overdrive, but as near as I can tell the tach stays stable when the truck does the violent hiccup. Any ideas on this? It could be the engine randomly cutting out for a split second, but it's just the level of harshness with it that makes me wonder. It shifts and drives normal otherwise. Luckily it isn't a daily driver for me so it hasn't really been too much of an issue. Any ideas?

 

[df2x4]

I'd check your ignition system. Plugs, wires, distributor, etc. I had a bad distributor cap cause this issue on my red truck. Nice looking truck!

 

[atrainsgt]

The whole ignition system had been replaced prior, so I was doubting that to be the issue. I guess it is possible though. I'll look everything over again. It's almost like you're driving along then fall in a huge pothole, then a few minutes later hit another huge pothole.

Thanks! I'm trying to decide on headlights Now.

 

[atrainsgt]

Any other ideas? Everything seems fine, plugs, wires, distributor, coil etc. Everything has been replaced. It seems to random, and harsh for it to be ignition related

 

[skylark]

Crank sensor is going bad. One bolt retains it, 3 wires to it. It is behind the harmonic balancer on the passenger side.

 

[99'Subourbon]

I'm also going to go ahead and throw out there: A clogged, or near clogged, fuel filter.

I had this same issue on my 02 F150, and seemingly randomly above 55 MPH, it would do exactly as you described, and give sudden, small violent jerks, up until 75 MPH, and it would be smooth again. I cleaned my TB, changed my spark plugs, cleaned my maf, changed the crank sensor, etc and nothing fixed it. Finally I spoke with my father in law and told him everything I did, and he quickly replied "It's your fuel filter". Sure enough... changed it and problem resolved.

 

[atrainsgt]

I don't feel like I'm wasting money replacing the cheaper items like the crank sensor etc so I'll go ahead and change it.

I replaced the fuel pump and filter recently due to a bad fuel pump, and that didn't help the issue any.

 

[98_k1500]

Cam retard properly set??

 

[Dethtats78]

I don't feel like I'm wasting money replacing the cheaper items like the crank sensor etc so I'll go ahead and change it.

I replaced the fuel pump and filter recently due to a bad fuel pump, and that didn't help the issue any.

I have a 96 K1500 that has a similar issue, but after scanning it with a computer found that the channels going to and from the EGR is clogged causing the shudder. Mine does it when traveling while maintaining same RPMs and not under a load like going down hill or flat ground. I have been considering trying to put some sea foam through mine. Has anyone tried it? Not sure if it works as I have never used it before.

 

[Jwidmayer1337]

Any updates on this issue? I'm having the exact same problem. I just replaced my fuel spider because the truck would randomly die but now I have this issue