I am TOTALLY new to this and REALLY have NO IDEA if this is where I am supposed to post or not, but here it goes, Its LONG, but I wanted to give you as MUCH info as possible


OKAY - HERE IS THE PROBLEM: (99 Blazer 4dr 4wd, 165,000 miles)

It is SLUGGISH. When, say at 30 mph, give it gas and it feels like its not getting enough gas or something, It goes but doesn't GET UP AND GO.

At a dead stop, Floor it, and everything SEEMS NORMAL and moves right along.
When MOVING, and floor it, it finally gets up and goes, but sluggish on its way up to full power. Its not the transmission slipping, it just kinda works its way up to speed-Kinda like the rpm's are being limited. It feels like it just can't get enough fuel or something .

AND - DURING Freeway driving, cruise control is even on, it will HESITATE on the freeway Intermittently, LIKE FOR A SECOND OR TWO, for no reason (i'm ASSUMING its the drag on the engine from the A/C and such.)

AND, since head gasket replacement, I noticed that when I take off, from a DEAD stop, "Regular takeoff", it sounds like it KNOCKS and (FEELS) like its going to stall, but then takes off. . It goes.

If I take off, from a DEAD stop, and "GENTLY" give it gas, there is NO hesitation and takes off just fine.

OKAY - HERE IS WHAT I HAVE DONE SO FAR:

I have a 99 Blazer 4dr 4wd, 165,000 miles. I had either a head gasket or intake leak (was driving to work, giving it more and more gas and it was getting slower and slower, engine didn't want to keep running, I pulled over and shut it off WITHIN 2-3 minutes and towed home - Water in oil -Milky but not bad, (I replaced lower intake gasket a few years ago), Compression low on #6 cyl. . . SO: For longevity - THIS IS WHAT I HAVE DONE!
I "LIKE" this vehicle!

(I have the dealer service manuals, the Craftsman tools and the knowledge/ability to FIX the problems - BUT - THIS one stumps me. I'm NOT a professional mechanic~!

I replaced BOTH head gaskets-new TTY bolts "degree torque was fun", FULLY chem-dipped intake and cleaned heads and even lapped the valves (since there was some leak down with water), new valve seals, all new gasket kit, upper/lower intake, New AC DELCO fuel injector kit and Fuel pump, fuel filter, Vapor Canister Purge Solenoid (seal was broken), ignition coil and ignition module, ACDelco Iridium spark plugs, plug wire set, cap and rotor, air filter, pcv valve, Replaced Fuel Pump relay because it was intermittently NOT turning on fuel pump (after head gasket change), new MAP Sensor SEAL-ONLY [did NOT replace MAP sensor], Cleaned MAF sensor and new Air Filter,

 

I have the same Blazer that you have ! you probably have the 4.3 like mine and you won't have no power house with that v6 ! but I see what your saying, you just want more get up and go ! I see you replaced a lot of stuff ! this is just a thought so don't quote me on this but did you check the fuel regulator, maybe it's not delivering enough gas to the injectors for more power ! ok try this just just for curiosity ! I found out I have more get up and go if I drop it in regular drive instead of overdrive ! I mostly use overdrive in town or cruising on the interstate ! with regular drive you have more power and better braking action ! you might try looking at the fuel regular and also try using regular drive to see if that helps ! this is just as good as any other place to find out your problems !