So I scanned my car a couple of weeks ago and about eight codes came up but the main ones I was concerned about was the mass air flow sensor, I changed that then this week my car started jerking and rpm would bounce up and down or would drop to zero I tried to figure out what could cause that nd the crankshaft sensor can cause that I scanned my car a couple days ago and crankshaft came up I changed the sensor yesterday it worked for a couple hours then my rpm gauge stopped working again I scanned it this morning and the crankshaft is coming up again! Anybody kno what the problem could be??