HiCustomer welcome to Just Answer!.
My impression is that removing the cap from the vacuum hose increased airflow to the engine, something it apparently needs. A factory-capped, dead-end hose like this would have no other effect that I can imagine.
When it originally would not restart, did you try using throttle (up to wide open) during the start attempts?
Do you see a CHECK ENGINE lamp illumination now when it's running?
Have you driven it to see if there's any power loss?
Or is it just an idle roughness problem at this point?
Talk in a few,
I was thinking the same thing as you. But there has to be an underlying issue somewhere and I don't know the first place to look.
To answer your questions...
When it originally wouldn't start, I did try opening the throttle all the way with no luck.
I have driven it, and there is a slight power loss...although it's very subtle.
When the cap is on the hose, it runs very rough now, and when I step on the gas the car just wants to quit.
Thanks for your help.
Oh...the check engine light was on at first, but I cleared the codes from the computer and now the lamp doesn't come on.
Thanks again for your help.
Hi Joe, good to meet you!
I had another thought on the subject. The vacuum hose that made such a difference in engine idle might also supply vacuum to the EGR system. If that's so, disabling the EGR might stop unintended flow at idle, fixing the idle problem.
Locate the EGR valve on the back side of the engine... pretty much above the transaxle area. The EGR system is composed of the valve, a vacuum/ backpressure transducer solenoid and a metal tube that ferries the EGR gas from the exhaust to the intake manifold.
Start the engine (vacuum hose uncapped) and check the tube for heating. Then cap the hose and see if it makes a difference in tube temperature.
If it starts flowing at idle, the tube will heat up like a toaster, so don't cook yourself. I'm thinking the EGR system is having issues at this point but it might be the tip of the iceberg. Check it out and let me know what you find.
It should NOT heat up if working correctly.
No rush, I've suddenly gotten busy here lol!
Talk in a bit,
I'm sorry it took so long to get back to you. The car belongs to my mom and I had to wait till she had time for me to look at it again.
I did what you said and started the car, then plugged off the vacuum line, but it didn't heat up at all. I kept it running for about 10 minutes with no change.
Hi Ed. Thanks for the response.
I did trace the vacuum line back to the intake manifold. It's not attached to a sensor but rather just a nipple that sticks out of the manifold. This has my baffled as well and the vacuum line isn't shown on any diagrams that I could find.
The car was running fine until we went out of town on Memorial Day weekend. I was driving my mom to meet some relatives and it was running great. After almost 200 miles, the engine started to stall and the check engine light came on. I had it towed to our destination and was able to start it a few hours later. The check engine light was still on and it was running very rough. So I took it to an Autozone and ran the scan, but it came up with the code that the #4 cylinder had a misfire. So I made sure the spark plug and wire were good and cleared the code from the system and it ran great from then on.
We came home on Memorial Day and it ran like a champ...until the next Friday morning when my mom took the car to church, it wouldn't start so she could go home. The check engine light had come on again and the car just wouldn't start. I couldn't get it to a scanner, so I figured it was the same problem as before. So I replaced the spark plug and cleared the system and it started, but ran very rough still. It was then that I played around and pulled the end off that vacuum line.
It seems to idle fine right aroung 800 rpm's. And above idle, you can tell there is some performance loss but not much. However, my mom said that sometimes, while she's driving, the car will surge just a little and that will last about 5 seconds and stop.
This didn't happen after a refueling stop and it was running 100% before this whole thing happened. And the check engine light hasn't come on since.
Please let me know if I may have missed anything. Sorry about the short story.
Ok, that makes perfect sense. The description you gave on what would happen is right on the money as to what happened on the way out of town. The engine sputtered and wouldn't accept acceleration at all, then when I got it to the shoulder of the interstate, it just quit.
The roughness seems to be steady but not really with a beat. Just really sporadic. And it does improve with acceleration.
I will look into those things tomorrow when I have my mom stop over. I will let you know how it goes.