Shakes Hard at Idle at Times

[cmybizness]

Hi, I have a 2000 Sportage. It runs decently (although sometimes there is a lack of power), but sometimes it hesitates at idle, and wants to cut off. Thing is, I've had tune ups done to it (new spark plugs, new wires, throttle body cleaned), but it still will run rough at idle at times. I must point out it doesn't do it every time; just sometimes.

I've had the check engine warning light come on, and when I took it to Auto Zone to get a reading, it indicates that it's the Mass Airflow Sensor is malfunctioning. I've replaced this thing twice before, but I bought them from Auto Zone, not from the dealer, so I don't know if that has something to do with it. All I know is that it continues to give me that rough idle at times, for instance, waiting at a red light. It's cut off about three times on me before, but I managed to start it back up.

It has about 105,000 miles, and I'm the original owner. I've had the timing chain replaced and the water pump, when it was at around 80,000. I've had the valve cover gasket changed twice; the first time it was because oil had leaked into the spark plugs, and the second time was just preventative.

I had it suggested to me that I adjust idle screw according to RPM at the throttle section, but I'm not sure how to do that. I've also been told to replace the cam position sensor...not sure of that either.

Does anyone out there have any suggestions or ideas what my problem could be? Thanks in advance for any help.

[Sportege]

You had the Check Engine Light (CEL) come on and checked you said.. if this came on around the same time as the problem then it is very likely this information would be important for us to determine your problem.. IE: if the code is a misfire or something to that effect. Was that CEL flashing during your problem? A flashing CEL is usually an indication that your engine is misfiring. If it is on steady then it is something less severe.
I mention misfire because I had a similar problem on my 01. Now and then, it would loose power at random times and then be normal again in a matter of 2-15 seconds.. totaly random. Seemed like it did it more under load (uphills). Then one day I started it and at idle it shook.. shut it off. started it again, and it was fine again. Then one day it did it and wouldn't stop. I was in a position that I had no choice but to drive it this way so I drove it 15 miles home. I had to floor it to get up to 55mph and that took me (no joke) a mile and a half to reach. And I couldn't go faster than 55mph full throttle on a flat stretch! The CEL was flashing the whole time so I figured it was a misfire already. I got home and shut it off. I decided to look at it in a few hours when the motor cooled off. But by then it was cold out so I let it warm up (still misfiring) for only about 2 minutes. I pop the hood and notice the exhaust manifold was glowing red hot!! Apparently when fuel doesn't burn in the engine, it does burn in the manifold and 1st Catalytic Converter. I suddenly thought about how long and hard I drove it to get it home and compared to the 2 minutes of Idle that resulted in it glowing like that, lol. I discovered something else rather amazing that night. I wasn't just misfiring on one cylinder, but two! I was running on only 2 cylinders! 15 miles on 2 cylinders!!! I was again impressed with my KIA even in the worst of matters she gets me home . The 2 cylinders that weren't firing shared the same coil pack. The other two cylinders share a different coil pack. So I thought that the problem was simply replacing the coil pack. $40 later, I was wrong. It still did it. I replaced the plugs and plug wires just to be safe. Didn't fix it. Out of desperation I use my voltmeter to check continuity on the signal wires leading into the coil packs (located above the spark plugs). All were in check except for one so I wiggle the wire and get a connection again.. AHA!! So I called and asked about a replacement. Well, the wires are entangled in the ($500) main harness, ouch! So I bypassed it with a quick splice connector and wire. Been running great for 2 years since. Well, Had a rusty connector a year ago I I just replaced it and greased it this time .
Just wondering if anyone else has ever had that problem. If I disconnect my bypass, it does it again so I know it's no fluke. I had to bypass the wire from the coil pack all the way to a separate wire I found kinda under the intake manifold going into the firewall. Weird thing is they don't apear to be related wires, lol.