Its an 03 blazer, 4.3L, manual. Randomly at start up it will idle rough- ranging between 250 - 1k rpm. Also it will sometimes just continue to drop in rpm untill it dies.. Any ideas?? This is only when starting it up. Tried cleaning the throttle body and cleaned everything, seemed to work for a few days each time but then it happens again. It's very intermittent.
Any help would be extremely appreciated!
Tony

 

When is the last time you did a tune up? Does it do this when it is damp outside? Any codes? How does it act when driving down the road?

 

just did a tune up a month ago, didn't help. only code is a knock sensor one, something that i've replaced twice but won't go away due to a slight lifter knock. drives perfectly though, just randomly will idle weird :/