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Dodgerench, ASE Certified Technician
Category: Dodge
Satisfied Customers: 3385
Experience:  30+ years Dodge/Chrysler exp., ASE Master with L1 certification. Driveability/ combustion specialist
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I have a 1998 Dodge Stratus with a 2.4 liter engine. On Friday,

Resolved Question:

I have a 1998 Dodge Stratus with a 2.4 liter engine.
On Friday, the car wouldn't start after I had driven it approximately 3 miles and let it sit for about an hour. Nothing I did would make it start again, so I had it towed to my house where I looked it over.
I found what seemed to be a vacuum line or intake feed that is connected to the intake manifold and runs up along the top of the engine and then crosses over toward the firewall. But there is a rubber hose on that end with a plug in it. This has been on the vehicle since it was manufactured. Anyway, I took a shot in the dark and pulled the plug out of the hose and the car started. Now, when I put the plug back in, it runs rough. It's not connected to any sensors on the manifold, just a nipple.
Do you have any idea why it would do this?
Submitted: 7 years ago.
Category: Dodge
Expert:  Dodgerench replied 7 years ago.

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?


Very strange!

Talk in a few,


Customer: replied 7 years ago.

Hi Ed.


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.


Customer: replied 7 years ago.

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.


Expert:  Dodgerench replied 7 years ago.

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.


Talk shortly,


Customer: replied 7 years ago.
Thanks Ed. I will check it as soon as I can and let you know what it's doing.
Expert:  Dodgerench replied 7 years ago.

No rush, I've suddenly gotten busy here lol!


Talk in a bit,


Customer: replied 7 years ago.

Hi Ed,


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.




Expert:  Dodgerench replied 7 years ago.
Hi Joe.
First... thanks for your patience! It's not often that I can't squeeze a customer in even when busy at work, but today was an exception.

With the EGR eliminated, I'm still not quite sure which direction we'll be headed. If the CHECK ENGINE lamp comes on again, by all means have the engine scanned if possible to see what it's trying to tell us. The 98 models don't support a customer code-read feature of any sort, so you'd have to actually make a date with a scan tool somewhere. Autozone parts stores and AAMCO transmission advertise free engine scans if that would help.

But EGR was only a small part of the picture, something that will crud your idle up but not prevent the engine from starting... especially if you use throttle. I'm still trying to imagine what this dead-end vacuum hose would have to do with idle quality if it didn't somehow also involve the EGR system. Here's a (really simplified) diagram of the vacuum hose routing of the 98 Stratus 2.4 engine...


If you could backtrack on the hose in question to find its source, it might shed some light on the subject. Let me know if it's one of the tiny hoses or something a bit more substantial.

How has the car been running since the time you first wrote, Joe? Is it still rough at idle? How's performance above an idle now?

Any more stalling? That would probably set the CHECK ENGINE lamp again if it did, so be sure to do what you can to obtain codes if at all possible.

Did this start soon after a refueling stop by chance? If so, there may have been water in the fuel, which will tend to dissipate over time as it's ingested by the engine. Thisis a wet time of year in many places, which makes me wonder a bit. Let me know.

One more question. Was the car running 100% OK before the stalling event... then the rough idle problem? Were there times when it might have had any of these problems before, if separately?

Customer: replied 7 years ago.

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.




Expert:  Dodgerench replied 7 years ago.
Your story is just what I hope for, Joe! Many thanks!

The #4 cylinder misfire might simply have been the one with the most incidence of failure... hard telling. But a single cylinder problem like that (with few exceptions) won't shut the whole engine down, so I figure it's just another piece in the puzzle.

My best guess at this point is that the fuel system was responsible for the stalling, as cylinder 4 would be the last to receive fuel if it trickled into the injector rail as a liquid. It's a bit of a stretch, but liquids will sometimes behave in this manner. Water entry into the rail would pick on cylinder 1 first, as its heavier specific gravity would tend to have it drop into the first available hole. By the time #4 cylinder comes up.. there might be nothing but vapor.

Loss of fuel pressure on a hot engine usually feels like what you described... the engine goes a bit soft, loses performance, won't pull itself at speed. Once off the road, it might idle (roughly) but won't accept throttle. It might stall a time or two and then... nothing. Is this about right?

None of this properly describes your idle roughness, however. Without codes or raw data to work from, it's hard to say just what the problem is with that issue. Describe the roughness.... is it a general rattiness? Or does it have a beat to it, as if a single or double misfire was present?

Does it improve immediately if the engine is accelerated?

Customer: replied 7 years ago.

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.

Expert:  Dodgerench replied 7 years ago.

If the car is nearby, pull each of the plug wires out to check for flashover. This is the act of spark following the outside of the spark plug upper insulator to ground, which burns a track in both the spark plug insulator and the inside of the boot.

While it's usually a problem that tends to pick on engine performance above an idle, it sometimes has the opposite effect, causing misfire at idle and near-idle only. Look inside the boots for a defined track (looks like a photo-negative of a lightening bolt) or pull the spark plugs. Any plug affected will have a permanently etched black line burned into the insulator, something that can't be scratched off with a thumbnail..

I think we have a solution on the stalling problem, but the idle roughness continues to evade me.

Do you feel that the roughness represents a 100% misfire of a cylinder? Roughness isn't always black-n-white... sometimes you'll have a reduced performance situation on a particular cylinder (or all), where you'll have 50% or so loss on occasion, but not a complete miss. You could compare this feeling to complete misfire by pulling a plug wire up a couple inches within the spark plug tube if that would help.

A brief sniff of the exhaust pipe might tell something as well. While it's not something I often recommend (for reasons you can imagine), sensing something other than normal exhaust might lead us to a blown head gasket. Coolant smells somewhat... butterscotch-y and engine oil has a telltale smell all its own, sometimes leaving a smoke trail, depending how effective the catalytic converter is. Check your fluid levels to see if something has dropped lately, which might be helpful in the diagnosis.

If the engine has more than 100,000 mies on a timing belt, you may have skipped a tooth from a backfire when the system (allegedly) lost fuel pressure. This will typically result in a retarded camshaft or two, which will affect idle quality disproportionately to above an idle. Just a thought.

There's no need to push the accept button yet, but I had to send this as an answer, per company rules.

Dodgerench and 8 other Dodge Specialists are ready to help you
Customer: replied 7 years ago.

Thanks Ed.


I will look into those things tomorrow when I have my mom stop over. I will let you know how it goes.

Expert:  Dodgerench replied 7 years ago.
Sound good, Joe.
Take care!