Ihave a 2000 Blazer and this thing is a mess.I have already been throughall thedeath-cool issues, intake manifold gaskets, water pump, and what not.It has beendoing this sinceI bought it, its drivable but its really annoying. whenI first start it up, and pull out of the driveway it hasNO power, it will creep through firstgear shift into second, and thats it, im stuck doing about fifteen mph, but only for about ahalf a block, or 60-90 seconds, then all of the sudden it just wakesupand most of the power comes back. ive ownd it for about a year now so ive figured out how to get arounf this, soin this first little bit i will hit the gas and it will jump like it has all the power for like a half of a second then fall on its face aagain, so i hit the gas pedal repeatedly reallyfast and i get all of these little jumps and i can make itdo 25-35 or more but i have to keep doingit to maintain speed until it decides to wakeup. once it decides that i deserve more power it runs good, it gets aro9und town alright but it still dosent have all the power it should. from a stop on wet pavement and pizza cutter tires i can mosh the throttle and it just dogs, sometimes it will back fire too (backfire on the intake side) the lack of power and the backfire point to a timing issue, but the timing is controlled by the computer, which make me think its a fuel problem. on long trips with no stops (30 miles or more) the check engine light will come on (in my experience means bad O2 sensor)but goes off the next day so ive never had a chance to get it scanned with the light on. until about a week ago it started shifting weird but only sometimes: basically what happens is ill take off from a stop ill get going until about 10 mph about the time it needs to shift and it will start surging kinda like if it shifted from first to second and back a couple of times(its not actually shifting back and forth just describing what it feels like) then it clears up and shifts into second shortly thereafter. this only happens if im driving like a grandma (or a poor college kid who wants to get every mile out of his gallon)if i step on it at all like half throttle it dosent do it. abouta day after this happend the service engine soon light came on so first thing the next morning i brought it down to the dealership and had it scanned it came up as a Random Cylinder misfire (i think the code was P3000) when i picked it up theservice engine soon light was off and it has been coming on and going offrandomly since then. so far i have done a complete tune-up : plugs, wires, cap, rotor.A new high flow catylytic converter,and fuel filter.I have checked the fuel pressure key on engine off it hits about 58psi and bleeds off to about 10 psi in about a minute or two, fuel pressure stays pretty constant 58 with the engine running.I have anew fuel pressure regulator sitting in the garage waiting to go in, i was wondering if there is anything else i should be looking for while im under there, or if im the right track at all. please help or im going to commit blazercide pretty soon. oh yeaand i have this awfull squeaking sound coming from the front suspension if anybody has any ideas on that.

 

I got about half way through your post.
Sorry, but I need some breaks in the action.


Anyways.
Sounds like a simple Tune-Up issue to me. When was the last time you gave it a tune up?

 

if your fuel pressure is dropping from 58psi to 10 in only a minute or 2 i'd definitely get that upper plenum off and take a look, may only be the FPR you say is already sitting in the garage waiting to go in or it may be more than that but i'd for sure find out asap

 

If your fuel pressure drops to 10psi within a minute but the engine starts again without flooding, I would think that the problem is with the check valve in the fuel pump. If it was the fuel pressure regulator, the engine would probably flood with fuel and it would be hard starting and foul the spark plugs.
The code p0300 could be caused by dirty fuel injectors. I would recommend cleaning the injectors. (Backfire though the intake could be a lean fuel condition, also the cause of no power.)