So my car is sputtering a lot at idle. Pretty much at the stop sign or the stop light, now the sputtering gets really bad and kind of almost feels like it wants to shut off but like it has like a sudden spark of life and revs up to about 7 800 rpms then sit back down to 500 and the sputtering kind of slows down a lot it’s so sputtering a little bit but not as bad as it was after it’s a little thing that it does but I talked to the mechanic and made say that since it’s drives okay and only on idle that it could possibly be the EGR valve. Not knowing anything about how to clean it how much it is to replace it pretty much anything but I was curious would that cause kind of like an exhaust smell in the car while it’s sputtering on idle and what did it cause problems starting up? Like the very first startup of the day it’s fine it starts us perfectly but anytime I try to start it up after that it’s like a sluggish kind of start.
What year is this Blazer?
And is the Check Engine light on?
Tester
@Greg_G This is your third post about problems with this Blazer of unknown year and miles. You had a loose battery connection but apparently never cleaned all the connections. It sounds as if just letting a mechanic get his hands on this and solve all the problems might be worthwhile.
…unless it is “sputtering”…
It can still cover a lot of ground, just takes longer. 
It sounds like it is running a little lean. That would explain why the problem doesn’t show up when the engine is cold, b/c then the mixture is much richer. The EGR is a vacuum operated valve that – when open – creates a small path for exhaust gasses to go to the intake manifold. It’s only supposed to be open at higher speeds and during accelerations, not at idle. If it was faulty & open at idle that would lean out the mixture and could cause this symptom. A mechanic could put a vacuum on the EGR control port and observe what happened to the engine and what happened to the valve pintle mechanism. That would provide clues if it needed to be replaced or not, and would be a good place to start the diagnosis.
If it’s not the EGR, a lean condition can be caused by lots of stuff. You noted you smelled exhaust, indicating an exhaust leak perhaps. An exhaust leak can affect the air/fuel mixture if your engine uses O2 sensors, which presumably it does. In that case good idea to focus on what’s causing the exhaust leak. Usually that wouldn’t be the EGR, more likely the exhaust manifold gasket or leaks downstream in the exhaust pipe connections. A mechanic would partially obstruct the tailpipe with the car on the lift and from the underside check all the connections for signs of exhaust gasses escaping.
I’ll add that my 45 year old Ford truck exhibited a very similar symptom a while ago, and it was caused by lean operation due to a clogged carburetor. Cleaning up all the air/fuel paths in the carb brought it immediately back to a smooth runner.
Unless you give us a reason WHY the mechanic thinks it could be the egr valve, you won’t get any agreement from us
What kind of diagnosis did the guy perform?
If you say he didn’t do anything else except retrieve fault codes, I’d say you need to find somebody else