Rough Idle when PCV hose sealed up
Thread Starter
5th Gear
Joined: Mar 2022
Posts: 5
Likes: 6
From: NC
Rough Idle when PCV hose sealed up
Hello all. I have a manual C5 coupe, 126K, started getting a hesitation/miss from time to time that can be pretty violent, toss a drink out of the cup holder violent, during acceleration after a shift. Not all the time, just periodically. I was also periodically getting a check engine light and P0172 and P0175 codes. I cleaned the MAF sensor, no change. Ran a few tanks of 95 Oct and haven't gotten the codes in a couple weeks. I hadn't changed the plugs in a long while, thought maybe the miss was unrelated to the codes and decided to change em with wires. I noticed the PCV hose connector at the intake by the throttle body was deteriorated with a hole in it. I replaced the short piece of hose and now with the hole closed up at the connector, it won't run smooth at idle. I disconnected the hose, and it runs great. Obviously, I need to get it connected. What would cause it to run poorly when connected? Would a bad or clogged PCV valve make it run poorly? I would think the open line into the intake would make it run lean and rough more than a clogged line, not that I know that its clogged, just a possible guess.
Any thoughts on why I would get rich codes periodically?
Any thoughts on why I would get rich codes periodically?
Racer
Joined: Jul 2011
Posts: 462
Likes: 123
From: Ozark Alabama
I had the same problem after replacing the Y rubber connector in the PCV system behind the intake. I thought I had broken something the car ran so bad.
Disconnected the battery for a few minutes and everything was fine.
Disconnected the battery for a few minutes and everything was fine.
Thread Starter
5th Gear
Joined: Mar 2022
Posts: 5
Likes: 6
From: NC
Thanks for the report...I will give that a shot. Mine stalls constantly driving around a parking lot, at a light, etc. Starts fine, and runs fine off idle...it actually idles fine after it starts back up...just doesn't drop off of anything above idle to idle without at least threatening to stall.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,627
Likes: 4,071
From: Cape Coral, Florida
Hello all. I have a manual C5 coupe, 126K, started getting a hesitation/miss from time to time that can be pretty violent, toss a drink out of the cup holder violent, during acceleration after a shift. Not all the time, just periodically. I was also periodically getting a check engine light and P0172 and P0175 codes. I cleaned the MAF sensor, no change. Ran a few tanks of 95 Oct and haven't gotten the codes in a couple weeks. I hadn't changed the plugs in a long while, thought maybe the miss was unrelated to the codes and decided to change em with wires. I noticed the PCV hose connector at the intake by the throttle body was deteriorated with a hole in it. I replaced the short piece of hose and now with the hole closed up at the connector, it won't run smooth at idle. I disconnected the hose, and it runs great. Obviously, I need to get it connected. What would cause it to run poorly when connected? Would a bad or clogged PCV valve make it run poorly? I would think the open line into the intake would make it run lean and rough more than a clogged line, not that I know that its clogged, just a possible guess.
Any thoughts on why I would get rich codes periodically?
Any thoughts on why I would get rich codes periodically?
Thread Starter
5th Gear
Joined: Mar 2022
Posts: 5
Likes: 6
From: NC
Thanks Simtech! Disconnected battery for a little bit, runs as good as it ever did now. Sounds like it resets settings and worked perfect. No more stalling, stuttering, etc.
