Missing/sputtering during accerleration

[gunhound]

1997 Blazer, 4WD Auto, 108K -

Spent many hours reading posts here and on the GMC Jimmy forum as well. Thanks for the great info......

Truck would idle just fine but when driving it would buck and sputter. Had to go full throttle to make it keep moving. Hard shift from 1 to 2, several codes: P0300,
P0758 (twice) and 1870.
At first I ruled out the switch because it would run without dying and dash lights always worked, but then decided to replace the ignition switch anyway. What a difference! Truck runs better and shifts very smooth now.
Had a code 102 shortly after starting, but it went away after turning off,restarting engine.
Still has a few misses while reving in park, probably need to re-clean the EGR valve.
Anyway, just wanted to post in case somebody else has a similar problem. Now to figure out how to smooth out the idle and I'm set until the next adventure.......

[muddog321]

When you put the switch in probably cleared the shift problem but get that trans fluid and filter changed cause probably dirty. Turn up done yet with plug wires? New PCV, air and fuel filter. MAF cleaned and add injector cleaner to start. Lots of the over 100k Blazers with the balance shaft get a slightly off idle it seems as the timing chain stretches and wear occurs, at least mine all have. All the bad intake manifold gaskets did not help my internals either!

[mike2004tct]

Originally Posted by gunhound

1997 Blazer, 4WD Auto, 108K -
Truck would idle just fine but when driving it would buck and sputter. Had to go full throttle to make it keep moving. Hard shift from 1 to 2, several codes: P0300,
P0758 (twice) and 1870.

Still has a few misses while reving in park, probably need to re-clean the EGR valve.
.......

EGR valve with similar symptoms on our Pontiac was the problem.
The bucking and sputtering would only occur at steading - straight road driving. Idled fine, and drove great under load. Replaced the EGR and everything was fine.

[gunhound]

Well my fix didn't last very long. (97 Blazer, 4wd, 4.3L, auto, 112K)
I just replaced the ignition switch and thought I had fixed some problems (see previous post)
The truck will idle smoothly, doesn't miss or die.
Once you accelerate the engine, its works hards to gather RPMs. As I hold the throttle around 3K - 4K RPM, the whole truck will shake roughly and it will continually miss and sputter. Runs very rough. Driving is nearly impossible since its so jerky. I did get two codes- P0102 and P0758.
I cleaned the EGR valve twice (problem before) and the MAF unit twice as well. No damage to MAF, wires intact. The codes will go away sometimes, then reappear.
I then disconnected battery, removed ECM fuse, recleaned MAF and EGR, (EGR always has carbon soot around plunger) - same problems.
The P0758 would come on even if I was just running the vehicle in park, so I question wether its a tranny issue.

Complete tuneup less than 6K back, (wires, plugs, cap, etc)

1. Could this be a dying fuel pump? From reading other posts, the fuel pumps seem to go around this amount of mileage. I figured I would get no fuel if the pump went, but that is why I am asking those in the know.

2. Could the EGR valve, if faulty, cause this problem?
Iv'e clean it so many times now I feel I should just replace it.

I do plan to check fuel pressure (gotta buy the tool first) and I also plan on pulling the plenum to check "washing" and to see if the regulator is leaking.

I was hoping to save myself some time and labor if possible. Thanks in advance.

[OverBoardProject]

I'm thinking that your coil might be packing it in. When this happens you just wouldn't get enough juice for it to run at higher RPM's

Here's something to read
http://autorepair.about.com/cs/troub.../aa062902a.htm