Paperboy1996

I have a 93 blazer 4x4 4.3L cpi when I come to a stop it will either idle very rough or die, however not all the time sometimes it runs like a dream. I just had the tranny rebuilt last month then this problem started a couple of weeks ago.
I have been reading several posts and figure it may be the EGR valve, I have heard of claening them not sure if this is very wise, If ok to clean what are you supose to use to clean them, and does anyone else have any better ideas.

Thanks for any help or sugestions you may have !!

Jon Teeter

I would say it is your EGR valve.If it has just an electrical connection then you can spray it real good with carb or brake cleaner even let it soak.If there is a vacuum line going to it then dont spray it because you might damage the reed ,just try to blow it out with a compressor.If the EGR is backed up pretty bad then I would also clean out the ports in the intake too.

Markgc

When the egr valve on my 350 Chevy Silverado was going, I had the same symptoms that you are mentioning. I also noticed that I would loose servo brake action sometimes and the brake pedal would be very hard with no power braking action. The engine would stall when driving slowly. In the end the truck became undriveable I messed around changing the MAP sensor and IAC per the shop manual until someone told me that it was the EGR valve. After I changed the EGR valve I had no problems.

What computer codes are you getting?

Mark

MT-2500

Welcome to your first post on AF.
Electronic egr valve?
If so and you remove it start the engine for a few seconds with valve off to blow out any carbon in intake. Go easy on cleanuing valve or pushing in on plunger. And get a egr valve with the screen in it that will help catch the carbon and keep it out of egr valve.
But before removing and cleaning unplug it when it is running good and drive it and see if it still idles rough. If so you have another problem.
Does it set any codes?
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

Paperboy1996

I have been unable to find anyone who can pull codes sucessfully autozone says they cant and advanced auto says there are no codes displayed! I do have the check engine light that comes on just after I start it but it shuts off in a flash??

Paperboy1996

MT - your saying when it is running good and I unhook the EGR valve it should stay running Good ?

MT-2500

Yes if it is the egr valve acting up.
When it is runnng good just shut engine off and unplug it.
Running with it unpluged will keep it from coming open or sticking.
It may turn on check engine light but the test will let you know if it is the egr valve causing problem.
If it keeps on running good unpluged then it is a egr valve or circuit problem.
Usually on the electronic egr valves it is a carbon ball that gets under plunger that makes them stick open.
A gasket with a screen in it will help keep the carbon ball out of them.
They have a habit of turning loose in carbon lose in the intake at certain times in there life. Which can be a real pain.
Let us know how it goes.
If the check engine light is not on with the engine running you usually do not have any codes
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

Paperboy1996

You guys were right on the money !!! I could not get my blazer to run right so I went ahead and pulled the EGR valve anyway, Sure enough there was a carbon ball blocking the plunger, Cleaned up the EGR valve and intake as best I could put it back together - It runs like a champ !!

Thanks for your help !!!

MT-2500

Thanks for posting back the fix.
Glad you got it going and fixed.
Sounds like you caught it in the act.
They do have a habit of doing that at certain ages/mileage and may do it again.
If so the next time get a egr valve gasket with the screen in it that will help catch the carbon. Most parts places have them. They save a lot of egr valve R & R.
Good luck
MT

__________________
Remember proper testing gives us the answer to many problems.
MT