Ok, I'm new here, have been lurking around browsing to see if I could find ANYTHING that would help me (either new or to see if it was something I had already done). I have a 97 2wd 4.3.. Recently began repairing/replacing to get it running again. (it had been sitting for 3 years, with some major and minor things that needed to be fixed when my brother owned it). My husband and I have spent a month working on it.

Replaced Radiator

All new spark plugs/wires/dist

New water pump

New heater core

All new o2 censors

All filters replaced and general maintenance upkeep done.

It ran fine up until a few days ago. At first, it would chug/drag/sputter only when first accelerating until the transmission changed into second. Now, it does it horribly at first and ebbs off but can still feel it at higher speeds.
My husband checked all the fluids, the radiator had a murky brownish color, so we flushed the system, finding a few clogs in the hoses (we figured from sitting so long and from previous "stop leak" being used on old radiator the gunk had settled). Afterwards, we test drove it, and while it needed to be done, the original problem is still there, only not quite as bad (and upon checking the fluid, it is discolored again.)

We are at a loss as to what else it could be. My husband is going to go through, starting tomorrow and clean/check everything, but I figured any helpful advise/tip couldn't hurt anything, if anyone has any ideas.

 

have you checked the fuel pressure ?

96+ Fuel System Diagnosis - Blazer Forum - Chevy Blazer Forums

also any engine light on ?

 

Could be an intake manifold leak &/or a head gasket leak. Take a couple spark plugs out & see what condition they're in. They should be a light chalky brown almost grey in color.
Also what brand or electrical components did you use? These blazers don't like most parts other than AC Delco, especially plugs & distributors.
I'd also look for vacuum leaks, clean the MAF & check the condition of the oil looking for antifreeze or gas in it. I'm assuming the engine oil was changed when you were working on it.
Also try a SeeFoam treatment for the engine & gas tank. You can Search in here & find the how to on both.

 

When your husband replaces the fuel filter have him check it to see if there's any restriction at all.
If there are you have a couple choices. The one I would take if you want to fix it once and be done is to drop the tank pull the fuel pump assy, replace it or rebuild with a new QUALITY pump for the application.. which pretty much leaves out anything but delco or delphi
Then clean the tank thoroughly and from that time on stay the hell away from mom and pop stations.

REALLY recommend the fuel treatment. The crud is probably well distributed through the system meaning into the injector / poppets

The bottom line is do you want to fix everything so you dont have to worry about the fuel system.. or would you rather string it out?

 

As my husband was going through and checking again, he found a bad wire on the ECM going to the ignition coil. So, pretty much we are either going to have to replace the whole wiring harness or just throw in the towel and get rid of it.

Thanks to those that responded. We did check/recheck everything and I only use Delco or Delphi parts, and it was all up to par. Again, thanks for the advice

 

{double post }

!!!! this one took over a minute to show up

 

Mouse chew or wearthough?

Options:
Harness fro junkyard. Either 96 or else 98 - 99 will prob work

get small ty raps, loop at wiring branches to hold form of harness, ... strip all tape off, inspect and rewrap. I've done it and it sounds like more work than it really is.