1999 Saturn SL2 code P0401

https://www.2carpros.com/makes/saturn/sl2
https://www.2carpros.com/trouble_codes/obd2

First of all thank u so much for ur donation. What I would try first unless u have already tried this is to remove the egr valve then Start the car if the car idles normal like the egr valve was still on then u have a plugged egr port. If the rpm only goes up a little then u have a restricted egr port. If the rpm goes up fast and it's really noisey then ur port is clear. Before I change every egr I do this to help clear out any loose carbon that might make the new valve stick and to make sure that egr port is not clogged or retricted. Also it's ok to reuse that egr valve gasket I reuse them all the time if I suspect a sticky valve or restricted port. Let me know what u find.

Yeah u have exhaust and vaccum on the ports one goes to the intake manifold the other goes exhaust manifold. Egr is short for exhaust gas recirculation. With the egr valve off and idling the rpms should have went up alot from the vaccuum leak if it stayed the same u have a blocked vaccuum port to ur intake manifold. If it was noisey and alot of stuff blew out that means ur exhaust port is ok. What happens is when ur egr valve opens it lets exhaust gases into ur intake manifold port unfornatley it also allows carbon from ur exhaust to enter that intake port going into ur intake manifold then eventually it becomes blocked causing ur code for egr flow. So ur going to have to clean out the port that sucks and doesnt blow. Un can try doing without taking off ur intake manifold which I suggest. Remove ur egr valve get some good stuff that eats carbon up like a carbon cleaner and put that in the intake port under egr valve let it soak for like 30 mins or so the longer better.U can try using some stiff bailing wire to clear also u could get a old spedometer cable cut a short piece of it fry the end put it in a cordless drill with the drill in reverse and use that like a mini hone to help clear it out also still using the stiff bailing wire for the hard pieces of carbon. If that doesnt work then u would have to remove the intake to acess better to port. But the clog is usually closer to part of where the exhaust comes in. Try clearing it without taking the intake manifold like I said if that doesnt work then check back in with me.

Sounds like a plan yeah if ur egr valve is off and ur car is idling and not racing u have a clog let me know hoe it comes out.