I posted this as a reply in another thread, but after receiving no responses I decided to start a new thread, especially since this situation seems so unique.

So a brief recap- my 80k mile '04 had a CEL or SES light on with a faulty purge valve code. Along with replacing the purge (thanks guys for the $40 Hyundai tip!!) I went ahead with a major 90k service. Up until the service she ran pretty good but MPG was poor at only about 9 mpg city. Also the idle seemed a little rough, and both the ignition wires and the Champion plugs looked like originals, so I opted for Magnecor wires and NGK Iridium plug replacements in the service. After some wrangling, the wires were definitely installed correctly. However, after service, the idle was bad and the truck started throwing multiple misfire codes. Spike recommended first trying a plug swap back to champions since I went with the hassle-prone NGK's.

Now before trying the plug or even a wire swap, out of necessity I started driving the truck short distances for a few days- according to other posts at a risk of fouling my cats or O2 sensors (hopefully I haven't done that!)

However, after maybe day 4 of driving maybe 5 miles a day with some start/ stops, a miracle occurred- spontaneous smooth idle!!!!!! As I think about it, maybe not completely spontaneous but close. The first 1 1/2 days my CEL light would blink upon start, going to steady a few miles later, all the while running somewhat rough. Then, around day two, the light remained steady, and idle seemed to improve but was still a bit rough. Then, at day 4, I went to start the truck and PRESTO- no CEL light and an idle smoothness that is close to great, but still not perfect.

I have to summize that the CEL light and the trucks performance are connected. Was the computer brain purposely changing the truck's mechanics while the CEL remained on, only to reverse the change once "cycled" through?

If so, this seems odd since my mechanic tried resetting the light many times after his absolutely correct install of the plugs and wires, only to have that light come right back on.
One would think if you get the work done right, the CEL responds accordingly and turns off right away. I also wonder if the purge valve P0441 code was interconnected here (tho the code went away immediately after the install of new valve and reset- again maybe a "cycling" thing?) What gives? And should I trust that all is well now?

 

UPDATE: the CEL light is back on, and trucks MPG performance is still crappy at around 9mpg city. The idle tho not incredibly smooth hasn't become worse, it seems OK. I have yet to check the code but I fear another misfire code possibly.
I beginning to think again that the wires were damaged when my mechanic installed them incorrectly the first few times, possibly slightly tweaking the metal contact points at the wire ends, or even stretching the wire and creating little tears? I did do the nighttime check and couldn't see any arching or sparks. Or back to the plugs, thinking they werent seated properly or a lack of plug grease...
Who knows, all told it still runs pretty good and has full power. Any help is greatly appreciated

 

Go get the codes read at your local parts store and get back to us with the 4 digit fault code number cause your guessing isn't cutting it.

 

The code was not a misfire but the dang p0441 code again- purge valve.
So now I'm off topic from the original post, maybe I should start a new posting titled "used hyundai purge valve trick but same P0441 code back 100 miles later"
Is this because I didn't replace the connector hoses and pieces, the ones that come with an OEM purge valve?
And hopefully Mike or anyone else might tackle the specifics of my original post?

 

I would be very concerned with using any mechanic who "installed them incorrectly the first few times"

Do you live in Mayberry???

Who is the mechanic there now? Is it Goober, i don't think even Gomer Pyle would have screwed up that bad....

Changing plugs and wires should be done by competent people.

 

If I recall correctly Goober and Gomer were quite good mechanics. Just slow in other areas. LOL

 

As you correctly assumed the mechanic wasn't all that, wasn't familiar with LR's, but to his credit- and I've seen this in other posts- he went by the confusing ignition wire diagram in the user manual, and not with the RAVE one. As soon as I printed that one out, he had it right on the first try. Possibly the user manual one is incorrect, or just confusing?

Would anyone please weigh in on my strangely spontaneous smooth idle issue?

And going back to the new P0441 code, what should I try next?

 

Send me your tele number and I'll be glad to walk you thru this.

 

they didn't switch the connectors to the purge valve and the secondary air valve did they. And is the damn thing actually tight.

 

Now that a few months have gone by after my "goober" mechanic somewhat botched install of my new Magnacor wires and NGK Iridium plugs- along with a few other things like a new purge valve- I'm no longer getting the occasional P0441 purge valve code (seems to have fixed itself?) but I did start getting an occasional misfire code, which at times will go away only to come back. Last read was a P1319 code, and I think that same code popped up before. Gas mileage also never improved beyond 9-10 mpg, and now the truck seems to progressively run rougher at idle.
I now have her with someone claimed to be a competent factory trained tech. He just told me my ignition coil pack is the problem, and that they are often the problem behind misfires and poor mpg at this mileage.
However this gets me thinking- before I swapped out what appeared to be perfectly good dealer installed wires and plugs (I found an old invoice from LR in Mission Viejo- changed at around 55k, but when I started this thread I thought they were originals)- I hadnt had any misfire codes. They started immediately after goobers install of the new goods around 78k miles, so I'm guessing there is more than a coincidence here? I also should add that the MPG was still poor at 10 mpg before swapping the wires/plugs (what prompted me to do them in the first place) but again, there wasnt the rough idle or misfire. More than coincidence? Could those few times of starting the truck with a mismatched wire install caused the bad coils?
Could it be that the coils were always at fault for the poor mpg? Never had an O2 sensor fault code, the sensors appear clean, truck always gets 91 octane, intake cleaned, oil maintained, etc. And then the dang misfire immediately after plug/wire install mystery...
Another thought- I did read up on other posts regarding ignition coils, and it seems that if the coils were truly bad the misfire codes would not be intermittent, and that the coil is often faulted when it is not at fault. I'm now worried that there may be coolant leaking into a cylinder?