EGR Valve

[pjharris]

My son drove his 1994 Chevy S10 Blazer 4WD from Iowa to Texas. It began running rough on the trip. When he arrived in Houston, we took it to the mechanic - who advised the EGR Valve was clogged (already had a tune up w/new plugs & wires, new Catalytic Conv & muffler), so they removed it and cleaned it - 3 days later it started the same thing, running rough - took it back to mechanic, cleaned EGR again, by the time we got home (12 miles) it was already missing and running rough again. Called mechanic - said to clean it again, it may take several times before it clears out all the carbon build up in the engine. Ok, now the question: We took the EGR Valve off, but don't really see anything to be cleaned, besides the surface of it. Can anyone tell us if there is anything else that needs to be cleaned?

Any help would be appreciated ASAP! We are beyond frustrated. Thank you all,

Pjharris
5/2/05

[jackass#1]

its true it will get clogged again. as long as there is carbon build up in the intake it will continue to do the same. its a very common problem with the truck. need to run so good fuel system cleaner though the tank and then add gas treatment at every fill up for awhile to clean it out. then to maintain it add to tank once a month. all it takes is a small piece of carbon to mess them up.
if you are still not sure take it to another shop for second oppinion.

[Mango™]

Check the plugs again, there could be some carbon on the plug(s)

[knishiya]

true ive read that carbon buildup is a tough problem for these engines. a good carbon cleaner is Seafoam. I bought it at Autozone and NAPA for $6. Read instructions carefully and dont pour too much in at one time, dont kill the engine. I put half in the carb and half in the tank. Cut engine and let it sit for 15 minutes. Now crank it up and drive it wide open throttle for 10 minutes to get all that carbon out. However, be prepared because once you start the engine up it will smoke like crazy out the tailpipe. I mean alot. Neighbors may call the fire dept if you dont get it out of your driveway quick enough.

Thats if the EGR is your problem. Check to make sure all vacuum lines esp at the EGR are connected and good. To test the EGR you can push up on the valve inside the EGR, the engine should stumble and act like its going to die. If it doesnt do anything, its a bad egr. you can also disconnect the egr vacuum hose near the sensor near the front of the engine and see what happens. It should stumble and act like a vacuum leak. If nothing happens the EGR could be stuck open.

Any check engine lights? Check Plugs, and Make sure wires are connected. Make sure right firing order to distributor.

good luck

[jg95]

Maybe the fuel injection, fuel pressure regulator