does this happen to anyone else?
i live in rhode island and my truck has 315000 miles on it. this only happens when its cold. when i start it i leave it running for at least 20mins before i leave with or with block heater. anyway from about 750rpm to allmost 2krpm the truck is reallllllyyy loud and deep. not normal but it has no loss of power or that. and as soon as i go under or above those rpm its fine. then slow down it happens again and it kindda shifts hard. then SOMETIMES if i shut it off and start it up again it goes away then sometimes that dosent work... it seems kinda like one cylinders not firing but i have no clue. it dont forget that this is only when its cold and SOMETIMES. anyone know what/why/how?