the truck starts great.. when in nutrel the big 460 sounds like a race car.. smooth, tight and strong.. when driving is starts making some weird sucking sounds and jerks around a little it also looses power.. typically up hils and the more often i drive it the more it seems to happen. Im not sure if its somthing in the vaccume system. The truck does need an exhaust. any info will help great thanks everyone

 

What transmission do you have?
Where is the 'sucking sound' coming from?