2000 I30 Rough Idling at Start

My 2000 I30 has 64K miles. A couple of months ago coil #1 was replaced. Recently, I noticed some rough engine idling in park(engine is vibrating as if a coil is bad) when I start the car. The rpms would go down quickly to almost 500 and then back up to the normal level and then in about 10 seconds the engine idles normally. There are no codes in the ECM, i.e. no MIL indicator. This doesn't happen every time I start the car but seems to occur on warm engine starts and again not evey time.

Now, a couple of days I started the car with engine cold and got rough idling that wouldn't go away. I also had an unusual smell coming from the exhaust. After several seconds I got P1320 and P0303 codes so my mechanic replaced the #3 coil.

I was hoping that my brief rough idling at starts would disappear but it is still happening. My mechanic tells me that if there are no codes, it's not the coil. Is he right? What else could that be? If the MIL is not on, there are definitely no codes in the ECM, right?

Reply to
Steve B.
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Exactly my problem...I have the Maxima in Australia (which is your I30)...there are no codes...and if your mechanic doesn't diagnose the problem correctly...then he's probably replaced the WRONG coil. You must replace the coil with a matching coil...not just another one that happens to fit. Go for the genuine replacement part...not aftermarket...not worth the gamble. The only way to test the coils is when the car starts juddering, start disconnecting the coils one at time by pressing in the spring-loaded green thingy and pulling in the opposite direction on the plug (I found a knife blade handy for this...BUT DON'T FORCE IT...once the green spring is pressed in far enough, then plug slides off nicely).

If the engine gets worse...that coil is good...if it stays the same...you've found the bodgey coil. Rog.

Reply to
Rog

The thing is the engine judders for only 10 seconds whil the rpms go down as explaine above. Everything returns to normal after that and there is no juddering except at those startups which happens very rarely.

Does your Maxima judder for the same 10 seconds with similar symptoms I described? Did you fix the problem?

Reply to
soccerman

Well, the problem is that it doesn't look like it's the coil. The engine would judder very very rarely and only for like 10 seconds while the rpms drop unsually. After those 10 seconds, everything return to normal.

Your Maxima also judder for only 10 seconds or so at start up?

Reply to
soccerman

Reply to
lwilliams

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