4.3 Vortec Running REAL bad

funair85 · April 25, 2003

Hi!

This is Joe. Im new to the forum! Seems like a nice place.

I think Mervz is a mod here???-Mervz are you around???

I have a problem with my 94 Blazer. It has the 4.3 Vortec, its a northern car, has 94,000 miles and is a 4x4.

We bought the car (under protest my GF wanted it, i hate northern cars ) in Buffalo a year ago. I always though it didnt have the power it should, but it seemed to run fine.

For a couple of months now, it has been really hard to start, usually taking 2 cranks to get it going.

Now since we've owned it, i have done the fuel pump, fuel filter, wires, plugs and other general maitenance stuff. Now the truck is running BAD. It grumbles, runs rich, (really rich so rich you can smell gas comming out of the tail pipe)

and very rarely throws a SES light. I think there's something wrong with the fuel injectors. Also during accelleration, it runs real bad until about 3000 RPM, then the HP seems to "catch" or all of the sudden run OK, not great but OK.

Im going to do some diag on it this weekend. Was just wondering if im on the right track and if anyone has experienced this before?

Thanks!!!

mcali17 · April 25, 2003

I had a '96 Jimmy with the 4.3L. One of the fuel injectors was leaking and my oil was becoming gas washed. This was causing the oil to thin out and the lifters to hang up. My family owns a gas station and my dad is a GMC dealer. I ended up replacing all of the injectors, couldn't tell which one was leaking, and intake gaskets. Truck went from night to day. I ended up selling it, with 94,000 miles on it to someone I know. That was a year ago and it is still running strong. Don't know if that is your problem, as I never smelled gas out the tail pipe, but if you pulled the dipstick and smelled the oil, it was very apparent.

Just a thought.

GM GIMP · April 26, 2003

Hi!
This is Joe. Im new to the forum! Seems like a nice place.

I think Mervz is a mod here???-Mervz are you around???

I have a problem with my 94 Blazer. It has the 4.3 Vortec, its a northern car, has 94,000 miles and is a 4x4.

We bought the car (under protest my GF wanted it, i hate northern cars ) in Buffalo a year ago. I always though it didnt have the power it should, but it seemed to run fine.

For a couple of months now, it has been really hard to start, usually taking 2 cranks to get it going.

Now since we've owned it, i have done the fuel pump, fuel filter, wires, plugs and other general maitenance stuff. Now the truck is running BAD. It grumbles, runs rich, (really rich so rich you can smell gas comming out of the tail pipe)

and very rarely throws a SES light. I think there's something wrong with the fuel injectors. Also during accelleration, it runs real bad until about 3000 RPM, then the HP seems to "catch" or all of the sudden run OK, not great but OK.

Im going to do some diag on it this weekend. Was just wondering if im on the right track and if anyone has experienced this before?

Thanks!!!

We have a '94 S10 Blazer 4.3 vortech that we bought

new. It's been a great vehicle and now has 113,000 mi.

One weak point to this year 4.3 is the injectors. GM even

had a TSB.

You need to replace the injectors (part is about $400.00)

not too hard to do if you want to do it. I did mine at about

100,000 mi. Had the same symptoms as yours. I think this

will fix yours too.

GOOD LUCK!

95whtZR2 · April 28, 2003

I have a 94' GMC Jimmy with the vortec 4.3L. It now has 130k miles on it, around 120k my truck would not idle very well, and would usually die at idle, and in general it ran like crap! It threw a check engine light and the code was 32, which meant EGR valve. I took the EGR off and cleaned it out, hasn't done it since....just a thought, because this is ten bucks vs. 400 bucks.......

TOm

Stepside Z · April 29, 2003

Welcome to GM-TC. Mervz is the site owner and I am the Mod for this forum. I have also been told of a spark problem with the 4.3's. Check out all the options the guys have written about. I hope you find all of your answers.

Z