Engine mis on rough road

Question

I have a 2005 gmc savana when driving on a rough road I will get codes po300,po420 and po430. This only happens on a rough road, on a smooth road it runs fine

Answer 1

Rough road and a P0300, this is caused by crankshaft variation, If a crankshaft relearn was not performed especially due to rough road condition. where a load is placed on the engine when the tire are on the ground and no load when the tire are free off the ground.