my 1994 chevrolet s-10 blazer will idle rough if i drive it for long distances. i can remove the egr valve, clean it , then reinstall it and normally it fixes the problem. the other day it started idling rough again so i went thru my routine. after reinstalling it ran well but when i road tested it. at 50 mph it cut off and started idling rough again. it starts easily back up again just idles rough. is this a indication that it?s time to replace egr? :(
Not really. More an indication that you have carbon build up in the intake passages to the EGR. First step is to go to your local GM dealer and get a can of GM Top Engine Cleaner. Bring engine to operating temperature and shut off. Disconnect MAF sensor and intake inlet. Start engine. You will get error code but that can be ignored for now. Slowly pour half the bottle of cleaner into the inlet pipe while keeping the engine from dying. You will probably see some white smoke coming out of the exhaust which is the built-up carbon from the cylinder heads. Now dump the remaining half bottle into the inlet pipe. This will kill the engine (if not shut it off). Allow the cleaner to "soak in" for about 15 minutes. While waiting, reconnect everything disconnected above (including the MAF sensor!) and unplug then reconnect the ECM fuse to reset the error code set above. Start the motor and watch lots of white smoke pour out of the exhaust. Good-bye carbon! For obvious reasons do not do this in the garage!
Run it a little bit and then pull the EGR out. Take a piece of stiff wire and make sure any carbon still in the intake is freed up. Now start the engine for a couple seconds to blow the crud out of the passageway. Clean the EGR really good and install it using a screened gasket such as
No, the first step is to open the EGR valve with the engine idleing and see if it slows way down or dies. No need to disassemble anything. Just suck it open with a hose and any port with vacuum.
NO vacuum port on a 94 EGR it is computer controlled, as are 99% of them from 94 on. The EGR on the 4.3 is a VERY common problem to the point that GM recalled them for replacement and updated software for the computer to change its opening times to TRY to keep the carbon from causing problems. It helps but they still have problems.
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