I am a new Santa Fe owner. It is a 2002 V6 LX. I had the spark plugs, wires, oil and air filter replaced as recommended by the dealer. However, I noticed that it will sometimes idle really slow when it is in drive like the transmission is engaging more than it should while sitting at a stop light. If I put it in neutral or park, it instantly goes back to normal. Also, this slow idling situation only happens rarely. Most of the time it is fine. However, I had it stall out on me the other day as I was about to park in a parking lot. This is when I took it to the dealer. They identified a few cylinder misfire error codes, which is why they recommended changing the plugs and wires. This cleared all the codes and it had a clean bill of health after that, but it still slowly idles sometimes. Does anyone know what might be causing this? Is it a transmission problem?

Thanks,
Rick

Welcome to the board! (IMG:style_emoticons/default/00000732.gif)

How slowly does it idle? What is the idle speed in gear and in neutral? Is the air conditioner compressor engaged? Are you using a lot of electrical accessories? How about the weather (hot/cold, wet/dry)? My '01 V6 will idle down to below 700 RPM at times, especially in hot weather with the A/C on, but will idle up to around 900 in mild weather at times.

Enquiring minds want to know. (IMG:style_emoticons/default/grin.gif)

Thanks for the welcome. During those times when I have noticed the idle going pretty low, the idle is probably right at 500 or just under. When it happened before, nothing was on and it was while I was sitting at a stop light. Last night when I noticed it, though, it was when I pulled into my driveway (fine up to that point), put it into reverse (noticed slow idle) then put it into drive (noticed idle was still slow) to put it into the garage. No AC was going, but this time the headlights were on. I noticed them slightly dimming when it was idling slow. I came back out about an hour later, started it put it into reverse idle was at about 900 in reverse and the same when I put it into park. Didn't seem to be doing that again. It is rare that it happens, but I would like to get it fixed if it is a true problem. In both cases where I noticed it occurring, it had been driven for 45 minutes or more. The weather in both cases was dry and one time it was 50 out and yesterday evening it was probably 70. If this is all it does, I am ok with it. I just don't want this to have been the hidden cause to the stall that occurred the other day that the dealer replaced the plugs and wires for.
Thanks for your help.

similar problem for me all the time no matter what the weather or anything extra going. it worse in the winter time if I hit the brakes too hard it will spike down to 500 then back to 700 and all lights(headlights, dash lights etc) dimm for a second when it goes to 500 and then the lights un-dimm after it goes back to 700 this is on drive or reverse.. park or neutral its fine.. 1000-1200?

(IMG:style_emoticons/default/00000732.gif) Rick,

Have your Throttle Position Sensor and your IAC sensor checked. The Throttle Position Sensor on a 2002 Santa Fe is likely failing, as these things die like flies after 90,000 miles old. Also, the IAC sensor provides a signal to increase/maintain a minimum of 750 rpm when the A/C compressor clutch engages and puts a new load on the engine. It also prevents a surge high idle when the A/C compressor disengages.

Byron

thanks byronguidry3732 for your help.. I will be sure to check into that.

Thanks Byron. I'll ask the dealer where I just had all of the plugs and plug wires replaced. Do you know if the Throttle Position Sensor and the IAC sensor would have an error code registered if they were failing? FYI, today it ran just fine to work, to lunch and then back home. It's hard to track it down since it is so sporadic.

Well, I took my Santa Fe to the dealer, and of course it was behaving without any idling problems at all. I asked them if the throttle position sensor or IAC sensor were failing. He told me not if there weren't any error codes or the check engine light present. After that it went a week or two without having the idling issue. Yesterday, however, it happened again. What it did was while in drive, it dropped down to about 350 rpms. I put it in park and it went up to about 1500 rpms and sat there. I put it back in drive and it dropped down to about 350 again. I drove it for another hour or so. It never stalled, but the idle was just slow while sitting still. Should I just have the dealer replace the TPS and the IAC sensors without error codes or a check engine light? Thanks again for your help.

Vacuum leak, perhaps? It sounds like it might be. If so, there are many possibilities. If it happens when you apply the brakes, the brake booster could have a ruptured diaphragm. Squeezing various hoses with smooth jaw pliers (to avoid cutting them) might give a clue where to start looking.

Replacing parts as a "maybe" can get expensive fast while not curing the problem. And not all faults, especially if they are very intermittant, will set a CEL.