2001 2.4 Optima Hesitation/Stalling Help?

Sounds like plug wires. I've replaced a few (but not a lot) of these on

2.4 Sonatas (the same basic car). Unfortunately, Kia says plug wires are 2/24 only. But the good news is that you only have two of them.

Presumably, you should have a check engine lamp if you have a misfire that bad. Do you? Did the dealer present to you that these items were going to resolve the hesitation, etc.? If so, I'd ask them what they're going to do about the $50. If you did all the things they recommended, used parts that were not defective, and did the job properly, then you didn't get the $50 diagnosis you paid for. What you got was the dealer telling you the required maintenance for 60k.

To check the wires, remove the plastic cover off the top center of the engine. Pull the plug wires off and look at the ends that go down into the plug holes. If you see carbon on the outside of the plastic, they're bad. If they look ok, put them back on the coils and rest them on top of the plugs (do not fully clip into place on the plugs). Then start the car. If one of the wires is arcing onto the plug hole wall, you can look down into the hole as you gradually pull the plug wire up off the plug and see the fireworks through or off the side of the plug wire. Sometimes the plastic just has a small pinhole you can't even see, but it sparks really well.

There is not a single light that has lit on the dash, no check engine or anything. Im really surprised it hasnt coded out.

You are correct, if we go back I will definitely explain what has happened and that the original diagnosis didnt help. I would hope that they would be fair about it. Regardless, Im trying to avoid going back just becuase of the hassle.

Im going to go ahead and order the NGK plug wires and change them since its something I should have done anyway it sounds like. Hopefully that solves it...

Thanks for the advice!

Jared

Just to check, pull the hose off the egr valve and see if the problem goes away. If so, your egr solenoid is probably stuck closed.

If you can find it, you can also check the purge control valve. It'll look like a round can about 1.25" in diameter and 1.25" long. It'll be mounted to the back of the intake manifold. Pinch the hose shut and see if the engine runs better. If so, the purge valve is likely stuck open.

I don't hold high hopes for either of these, since they don't typically cause performance issues except at idle. I have seen them go bad and not set codes in the ways I describe, however.

Ok, I put the new NGK wires in. They look like good quality wires by the way. It has cured the hesitation during acceleration! Whew, it feels alot better. It still acts like it is going to stall at idle however. I am going to try your EGR and PCV tricks to see if I can determine what needs to be replaced. Are these parts only available through KIA, or are there aftermarkets available?

Thanks,

Jared

I was trying to investigate my idle issues tonight. It only seems to act up when the car is in Drive. Anyway, Im having trouble identifying the location of the EGR and PCV. I felt around on the back of the intake manifold and found a sensor with an electrical connector in the center rear, and what looked like a 12.5mm hose going to the brake master cylinder...very confusing.

I played around with the three rubber lines going into the top of the throttle body with casting marks labeled P,E,A on the throttle body. Pinching off tube A makes the car stall. E and P dont seem to have any affect.

So, can you give me a better idea of where the EGR and PCV are at?

Thanks in advance,

Jared