I have a 93 Chevy p30 stripped chassis (step van) with 5.7 v8 tbi with at. The truck is stock except for egr delete. Sometimes after running a constant speed for 10 minutes or so, I get what I am calling valve rattle (machine gun like noise) when I come to a hill and press the gas pedal to the point of downshifting . I let up immediately and it goes away. If I don’t react quickly enough, I get code 43 knock sensor which I would think is to be expected. I was also getting 42, ignition bypass error, until I routed my spark plug wires away from the connections on the distributor. This engine is a jasper replacement that I have run about 8-10k and it has done this from the beginning. I let up as soon as I here it and downshift manually if need be to avoid it happening again. Sometimes I can drive it 2 or 3 days in a row with no issues. The distributor was put in new with the engine. I have also replaced the tps. Being that this is a stripped chassis, there are no bells and whistles on this one. I have also checked the wiring from the distributor to the ecm and checked the ecm for bad connections and bad solder joints. Doesn’t appear to be anything left but the ecm itself. Has anyone ever had a similar issue? Help is appreciated.
Btw, I have the interface and have downloaded tunerpro. The strange thing is (to me), it will not act up if I have tunerpro recording a file. If tunerpro is connected and up, it will still do it, but once I start recording, it will not repeat the issue.