I have a 2000 model Sonata 4cyl 2Litre that has developed an engine miss. When you first start the car it idles will for the first 10 to 20 seconds then the miss starts. when you try and drive the engine sometimes sounds like it is running on three cyls and then the fourth will kick in. This is the same under load or not.</P>


Anyone have any ideas?</P>

 

It will be one of two things.</P>


1. your crank position sensor wil be playing up, starting to intermittantly open circuit.</P>


This problem won't be so easy to diagnose at home.</P>


2, the more likely scenario is that you will have a high tension lead that will be starting to track.</P>


Remove the engine cover, and remove all of the leads, one at a time so you don't get them mixed up! Then inspect each lead carefully. If the lead is faulty you will notice a mark on the lead tip or shaft that is surrounded by a white powder type substance. This is where the spark is "leaking".</P>


Inspect all of the leads for this type of fault.</P>


If you cannot detect any fault using this method, then you need to follow the next procedure.</P>


Start the engine and allow to run until it begins to misfire, now individually pull each spark plug lead off the spark plug just a bit.</P>


You will notice that the car either runs worse, or the same. If you pull the plug lead and it runs the same, then you have a problem with that lead or spark plug, comletely inspect both. If the spark plug is at fault then you will have black burn marks running down the porcelin of the plug, if it is the lead you will have the burn marks on the plug lead which will be surrounded by the white powder.</P>


</P>


Good luck.</P>

 

Garry, I had the same problem with my 2001 Hyundai 4cyl. I had tested all of the things Dr. Hyundia mentioned in his previos post, but those items weren't the problem. It turned out to be the Hose that runs from the intake manifold to the PCV valve. The hose had a small hairline crack in the bottom that was almost invisible. I replaced this hose with a new $2.00 section of hose and the car runs like new again.

 

I have also seen a number of hyundais that plug wire seems to break down and carbon track the terminal on the coil pack

 

First, what I use is a spark tester. It looks like an ink pin with an LED light on top. You touch the spark plug wire or coil pack and the LED lights each time the spark plug fires. 2) Take a can of carb or fuel injection cleaner and spray around the intake and vacuumed lines. When the engine smooths out you have found the leak.