Rough Idle...Any Suggestions???

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PowrSlave

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Protege5
In about two days my car has gone from healthy to really bad idle. It will idle rough and then dip down and almost stall. The problem came out of nowhere pretty much. I am not noticing any sluggishness while driving under throttle though. The OBDII scanner says: P0301 "Cylinder 1 misfire"

A few thousand miles ago I had a similar problem but the car also considerably lacked power above 3k rpm and was quite sluggish and gradually got worse over a few hundred miles. I replaced the plugs and plug wires/boots and that solved the problem, but now I have this rough idle that seems to have come out of left field.

Does anyone have any ideas what might be causing the problem? I can trust that the scanner pinpointed the problem cylinder accurately? Any help is greatly appreciated guys.
 
you need to clean your egr valve,do a search about "egr valve cleaning",you ll see everything you need to know!
 
code 301 means theres something wrong with the first cylinder.
can be fuel or spark, but since you say u changed the spark plugs and wires already Id say theres something wrong with the injector.
 
oh yeah, if I were you I woulndt floor the car...you dont wanna go lean if theres really one injector not providing enough fuel. Or it can be sending too much, but when it sends too much, it shouldnt hesitate when u floor it, only low rpms.
 
swap injectors around & see if the problem moves. Check for manifold vacuum leak as well. I assume oyu pulled the plug and inspected. What did it look like?
 
It might be the Injector or pump. But before you replace those, clean the EGR valve and see if it fixes it.
 
I'd pull #1 plug and check it and also make sure that wire is connected snugly when you put it back on. Not that this would throw that code, but how old is your PCV? A clogged PCV could cause your idle issue also. Checking both of those two items is a snap versus pulling off your EGR which is not hard but a bit more work.
 
Hmm, okay I am taking a look at the plugs to see if there is foul up, but which cylinder is #1 on the FS engine? My service manual is a pretty crap version.
 
that exact same thing happened to me a few months ago. cleaned EGR valve, problem solved.
 
Wierd. I would imagine that all cylinders would be misfiring if the EGR was the culprit. Guess I can't really rely on the ECU throwing codes as much as I thought huh? I will try cleaning it today.
 
Anyway, the plugs all look fine no fouling whatsoever from what I can tell. They only have about 5,000 miles on them anyway as do the plug wires. I do notice that plug #1 (the one that threw the P301 misfire code) did have a very small amount of "burn" on the top of the plug where the wire meets, which would indicate a problem with arc, but the wire is so new I don't see how it could be, though new plugs/wires solved the problem the last time.

About the EGR. I am unable to get the four screws off that hold the solenoid housing on. They are practically welded in. WD40 didn't work, and PB Blaster didn't work. I ended up just flushing the valve housing with BrakeKleen while the solenoid is still attached. Hope this isn't a bad thing though. Any comments on this part of it?

I will put the EGR back on and see if what I did helped any, though I am not expecting much.
 
PowrSlave said:
About the EGR. I am unable to get the four screws off that hold the solenoid housing on. They are practically welded in. WD40 didn't work, and PB Blaster didn't work. I ended up just flushing the valve housing with BrakeKleen while the solenoid is still attached. Hope this isn't a bad thing though. Any comments on this part of it?
Click to expand...


Use a pair of vise grips to lock onto the small screw after it's been soaked with PB blaster. That seemed to work for me.
 
UPDATE: I cleaned and re-installed the EGR and the rpm drops continue at idle. I am starting to think the plug wires might be faulty but I really don't see how since they only have a few thousand miles on them and the plugs all look fine with no fouling. Maybe the coils are going?

Thekid760, I went ahead and just sprayed and brushed a bit inside the EGR without removing the solenoid since I wanted to just get it done. Didn't think of using vise grips argh thats a good idea.

Anyway, after searching the forum, I see that, often times, cleaning the EGR did not solve the problem. Besides, shouldn't a gunked up EGR cause more than just one cylinder to misfire?

Does anyone else have any ideas about what might be causing this?
 
I just had the same problem. Our mechanics originally thought it was fuel injector valve, they changed it which seemed to correct for about 2oo kms, then severe shaking started. Managed to get it too them in this state so scope was able to detect faulty coil. It may be your coil. Car seems fine now, but just noticed engine light just came on again. No shaking though.
 
Coils are $90 bucks each and I might as well replace both if I am going to do one. $180 is a lot of money for a "maybe it will fit it" solution. This is frustrating.
 
PowrSlave said:
Coils are $90 bucks each and I might as well replace both if I am going to do one. $180 is a lot of money for a "maybe it will fit it" solution. This is frustrating.
Click to expand...

Have you looked at NAPA lately? The last time I purchased coil packs I got a cheap set of wires and plugs w/ the coil packs for around 100 bucks.
 
Are you serious? both coil packs and a full set of wires for $100? Even our screwed up dual wire/boot setup? I'll definitely check it out.
 
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