GMC Repair: 87 K5 Blazer stalling, k5 blazer, vacuum hoses

Question
I have an 87 K5 Blazer I know not a GMC but pretty much the
same thing.  Well it was bought with the intent of a mud
truck and last weekend stalled it in some deep water.  
Changed the plugs and it starts and seems to run fine.  My
problem is when at idle if i rev it the rpm's after going
up come down way to low almost to the point of stalling and
if I come to a stop to quickly or change gears from park to
reverse or park to drive the rpm's drop so low that it
stalls.  I think that it may be the TPS am I right or is
this a vacumm problem or something alot worse?  Any imput
wound be greatly appriciated thank you.

Answer
i would check to make sure that you have removed any and all water from anywhere it might have gotten into, especially vacuum hoses, canister etc.  Not sure if 87 is equipped with TPS, but I would check to make sure there is no water in the intake or engine