Hello i recently bought a 2016 Chevy Silverado LS 4.3 l and when i normally accelerate it barely passes 2000 rpm it always change gears around 2100 rpm when i press the pedal to the floor it doesn't pass 3000 rpm also i noticed when I'm driving on the hwy when i reduce speed and accelerate back it pickup speed very slowly i had the throttle body cleaned i cleaned the maf sensor i use fuel additive from time to time i have no engine light it does have a quick start i was suspecting the spark plugs i do have some minor ticking noise underneath the engine that is hard to notice i was told could be fuel pump that is failing or injectors or in limp mode i never had a Silverado before so not sure if that's how chevy trucks are please help thanks in advance .