On two occasions I've taken long trips of about 200 miles and then the car runs rough and won't idle, diagnosed as EGR problems. Both times I've taken it to a shop and they only charged me about $70 and said there was carbon build-up making the EGR valve stick open. I guess this is a known problem from looking at posts. I am having a hard time figuring out where it is on a 1993 S10 blazer with a 4.3 Vortec fuel injection. I know what it looks like but I don't see it, unless it is right there at the front of the intake manifold. I'd like to be able to unstick the EGR myself and save a little cash if this happens again. Luckily these two shops didn't soak me too badly.

Look at the front of the engine where the air tube from the air cleaner goes to, that would be your throttle body. Below that and a little to the left is the LEGR.

If it's a carbon problem wouldn't switching to a little hotter spark plug not help out the situation in the future?

Carbon builds up over the years then starts to flake off. When the EGR valve opens any loose flakes get caught in valve opening. If your doing long trips or extended high speed( or you could say anytime the valve is being opened for extended periods of time) the greater the chance of geting a flake of carbon stuck in the valve opening causing it to run like shit. ya this is a common problem and a current problem for me too. The only real way to stop it is to pull the intake off and have it cleaned, But there is one other thing you can do if you dont mind the "Service Engine Soon " light on all the time is to disconnect the electrical connection from from the EGR valve so it does not open. When its time for emission testing plug it back in so it doesn't fail.

I don't really like junk like egr valves, cat converters, and what not, but I'm told that the EGR helps the motor run better during the cold weather. Although I'm also told that it hurts performance during the warm weather... so your probably best off to just change it, and everything should run right.

I still like old school performance best (high compression good breathing motors, and light weight cars)

Carbon builds up over the years then starts to flake off. When the EGR valve opens any loose flakes get caught in valve opening. If your doing long trips or extended high speed( or you could say anytime the valve is being opened for extended periods of time) the greater the chance of geting a flake of carbon stuck in the valve opening causing it to run like shit. ya this is a common problem and a current problem for me too. The only real way to stop it is to pull the intake off and have it cleaned, But there is one other thing you can do if you dont mind the "Service Engine Soon " light on all the time is to disconnect the electrical connection from from the EGR valve so it does not open. When its time for emission testing plug it back in so it doesn't fail.

The EGR in a '93 4.3 Vortec is a Linear EGR. If he unplugs it, he will have the SES light and the computer will more than likely go to open loop and his fuel economy will suck. Remove it and clean it.

There Is A Problem where corbon gets pushed up into the egr and gets stuck in the valve. The dealer now has a fix where a screen is in the egr gasket ,and this keeps debris out of the egr valve.

Another problem i have had is the egr will not close if bad charging system causing to beless than 12 volts at any time. Every thing will be fine except egr is very sensitive to volts below 12

I know what it looks like but I don't see it, unless it is right there at the front of the intake manifold. I'd like to be able to unstick the EGR myself and save a little cash if this happens again. Luckily these two shops didn't soak me too badly.

It's in front under the throttle mechanism. It's hard to get your hands in to draw the 10mm bolts out.

I've done this a number of times and usually had pieces of carbon holding the pintel open. This time, my SES light was on and using a paper clip across pins A and B of the diagnostic connector, I got the dreaded EGR code (I think it was 34 or 35). When I pulled the EGR unit there were no pieces of carbon holding the pintel open. Maybe they fell out in the process of pulling the EGR?

Does anyone know how I can test the EGR to determine if the pintle is functional. Can the engine be started and run without the EGR mounted to see if the pintle is commanded by the ECM?

Also, I've heard of a gasket with a screen that keeps the carbon particles out of the pintle. Where can I get one? Autozone? Kragen? Napa?

This time, my SES light was on and using a paper clip across pins A and B of the diagnostic connector, I got the dreaded EGR code (I think it was 34 or 35).

Actually 32.

Does anyone know how I can test the EGR to determine if the pintle is functional. Can the engine be started and run without the EGR mounted to see if the pintle is commanded by the ECM?).

I searched the forum and found that I could run the engine without the EGR mounted for a short period of time to blow out some of the carbon.(although it's supposedly a huge vacuum leak and the RPMs will get high)

Also, I've heard of a gasket with a screen that keeps the carbon particles out of the pintle. Where can I get one? Autozone? Kragen? Napa?

Again, searching the forum, I found a Standard Motor Products VG57 and www.tomco-inc.com part that has the screen for blocking carbon particles from interfering with the EGR pintle (mainly keeping it from closing).

So far I haven't found a local retail supplier of the screened gasket, but that's mostly because I haven't exhausted all the possibilities. My plan now is to follow all the advice regarding cleaning the EGR. Then, I'll try to disloge whatever carbon I can through the openings into the manifold with a wire, in case they're plugged. Vacuum whatever was disloged. Then try to blow out whatever carbon is still there by running the engine without mounting the EGR. I'll button it up using the standard gasket this time around and if it works, I'll look for reasons for excess carbon.