After running at 3500 rpm for about 30 minutes. The engine spits and sputters and cuts out. Restart and idles fine. Right before it starts cutting out . The valaves start rattling. Like the timing is way off. We are thinking that it is a overheating ignition module. . Has anyone had this problem?
Could be the lifters collapsing. I had a 4.3 in a 96 Blazer adn 7 lifters collapsed overnight. After that it would take 5-10 minutes to get the pumped up again and the engine to calm down.
My brothers boat also has an issue like this where when he runs WOT for more than a couple of minutes, the lifters start losing pressure and the valves start rattling. His is a 1985 5.7 260HP though so it is old and tired.
I had a very similar problem last year except the knocking noise. Turned out to be the checkvalve on the fuel tank that the fuel line attaches too was almost totally clogged with gunk. try taking it out and cleaning it and see what happens.
Yes it could be the ignition module. I would isolate issues associated with the distributor such as the module, cap and rotor and of course check the timing...
4.3 cutting out
Linear Mode
