ok so i have a 94 s-10 blazer v-6 4.3 vortech enginewith 77 thousand miles on it

replaced so far: spark plugs, spark plug wires, fuel pump, fuel filter, EGR valve

i have found a better word then "burping" at ideling, it's been misfiring, after about 15 seconds after start up one cylinder will misfire constantly, then another will misfire, which gave the shaking and "burping" when i replaced the spark plugs i noticed on two of the cylinders had wet threads. they weren't soaking and the ends were dry put they had some gas on them.
Everyone told me it was a vaccuum leak so i did a little digging. I started to take off the vaccuum lines off wile it was running and the misfireing stoped for a couple of seconds before continuing, but it wasn't as bad. but when i plugged the lines all back together it got a little worse and more constant.
I don't know if that has any significance to my problem

so the only possible thing i can think of is bad injectors
and if it is I know injecotrs aren't that much $, but how difficult is it to replace them?

 

double post sorry

since i have decided that changing my injectors is the only thing possibley wrong(no codes from anything) I was wondering.
I know these poppet injectors are problem prone and since i can't upgrade to the new spider siystem GM came out with. will teh aftermarket's i get still be the flawed poppet design?

 

Hey Thor,
I'm having a simular Prob with my 95 4.3liter, I've replaced plugs,wires,cap rotor, cleaned EGR,
Checked fuel pressure, replaced Vac. Lines replaces fuel filter, Cleaned every sensor I can think of
and changed a bad O2 sensor but have the same issue. There are no SES codes except for the O2 sensor I have had problems with injectors before replaced the spider setup twice, It seems to have the same symptoms as when the injector went bad so I would have to say that may be the problem. If anyone has any suggestions please let us know.

 

Miksfiring and no P030? code?
Anytime it misfires it should trip a P0300 code of some sort. IF it had a number at the end that would tell you which piston, a 0 means multiple random misfires. You both need to have your codes pulled to be sure there aren't any stored. Your local autoparts store should do it for free.

IF you truely do have a misfire your possible causes are cheap incorrect spark plugs, cheap or incorrect spark plug wires, cheap or incorrect distributor cap/rotor. You both replaced your plugs and wires. These are high performance engines and require top of the line replacement parts. AC Delco....

Search the site for P0300 code. There are some horror stories, and most of the time it comes back to the replacement parts.

IF you have a poppet problem, seafoam through the gas tank is a hell of a lot cheaper thennew poppets.

When was the last time you changed your fuel filter and air filter?

 

I changed my fuel filter about a week ago along with the plugs wires cap rotor, using Delco
replaement parts, checked for codes with My father's tech 2 scanner only had the code for
The O2 sensor and cleared it afterwards, My prob is weird it is intermitant only does it at an idel
when I start the truck cold it's fine if I rev it and then the idel comes down it will have a slit rough idel and as soon as I give it a bit of throttle it's fine, Truck accels fine with no skipping only does it at an idel
Any other ideas?

 

the first thing i changed was the fuel filter, I have already ran an stp injector cleaner threw and currently a bottle of seafom, the spark plugs i have bosh platnum so not low grade, and high performance wires around here are like $80 so i got the midgrade for $50, i gues i could replace the distributor but like i said i have only 77 thousand on it but it's been sitting for8years being run intermitenly

same symptoms that gscrippler has it only does it at ideling and when you rev the engine the symptoms go away, mine also does this at low speeds (less then 5 mph) or when you just let it roll with the engine running, usually when i do this it stals.

I can get the codes from it agian just to see but the only one i got was a code 12? think that was an alls ok code or something
i'll dig it up from one of my previous posts

 

Find your vacuum leak... You got one, you just aint found it yet...

After that clean your MAP/MAF sensor, and then check your TPS.

 

I changed my vaccum line from the Manifold to the T and the short one that goes to the black ball on the hood. Are there anymore you can think of on my 95 4.3 vortec? that would cause a problem?

 

Hey Thor, Today I tried 2 things to solve my issue, I removed plug wires from distributor and
when i reinstalled them I used a small screwdriver to hold up part of the boot to allow for trapped air to escape, I read on this forum that air get trapped in the boot and when it heats up it could cause a prob. and I also went vacuum line hunting I found one that attaches to the bottom of the throttle body,it runs to some plastic tubing to A sensor that is attached to a sensor on the drivers side of the plendum I made sure it was connected better. one of the 2 seemed to improve my conditions. I am going to replace the complete vaccume line with new hose eliminating the plastic tube and see what happends I drove about 50 miles and it only rough ideled 1 time. Give it a shot, Also Hanr3 for the tech tip

 

well now more problems arise

today my blazer started to miss wile accelerating and sometimes at high speed (60 mph) but it was an on, off thing sometimes it did this and sometimes it didn't, i don't know if it was the sea foam i'm running threw it

it also stalled twice wile at a complete stop. but now the missing at ideling is an off, on thing, sometimes it will do it and sometimes it won't.
second i have always smelled a faint scent of gas but now it's more promonent, i think it might be the fuel pressure regulator which i herd absolutely must have a high quality or it will run like crap

also gscrippler you have a new style blazer i have an older model i can't see any vaccuum line going to my throttle body i don't know if there is suppose to be one there.

no check engine light comes on when all of this is going on and no codes show up. It might be the new wires i installed casue they are midgrade but i know it's definetely not the spark plugs