[Origin]

So my friend is having problems with her car, I tried troubleshooting and nothing I came up with seemed to be the problem.

-01? Kia Sportage
-no idea on miles
-If its in park/neutral it will randomly drop to ~250-500 rpm and occasionally even stall out
-Will also climb up to around 3k rpms in park/neutral at random and sound like it wants to blow up.
-Sometimes will not accelerate when the gas petal is pushed while in gear
-other times she will be driving normally and it will go to ~3k RPM no matter were her rpms were prior to that, but it will not accelerate her if she is under 3k, but it will engine brake and decrease speed if she is over 3k.


I haven't had a chance to drive it around and actually feel it, but all I have come up with hasn't seem to be the case.

Other random info is AC being on or off has nothing to do with it, and and it is not overheating at all(given the temp gage is working properly) And the transmition fluid is topped off.



THanks for any help.

[bergs]

Originally Posted by Origin

-01? Kia Sportage
-no idea on miles
-If its in park/neutral it will randomly drop to ~250-500 rpm and occasionally even stall out
-Will also climb up to around 3k rpms in park/neutral at random and sound like it wants to blow up.
-Sometimes will not accelerate when the gas petal is pushed while in gear
-other times she will be driving normally and it will go to ~3k RPM no matter were her rpms were prior to that, but it will not accelerate her if she is under 3k, but it will engine brake and decrease speed if she is over 3k.

Any back firing during any time?

Does it start all the time?

Last tune up was when?(miles would be helpful)

Carefully check all the connectors in the engine bay for corrosion.

You say the vehicle will go to 3k while in gear? Does it downshift or does the motor just spin up to 3k?

Throwing any codes? "Check Engine" light?

[drop]

i'd guess a vacuum leak or bad tranny.

[ssg]

weirdness, not familiar at all with those vehicles but do they use an (intake) manifold pressure sensor? Though usually that wouldn't change idle too too much.

Almost wonder if the fuel pump is toasted...

[Wishbone]

TPS

[CBRGuru]

The problem is its a Kia. If its throwing codes you can take it to Autozone and have the diagnostics run.

[TIMMYDUCK]

My 1st guess would be it's not running on all of it's cylinders.

See if you can find a non-firing cylinder .

[FireboltEric_MA]

The fuel tank may be getting stuck in a vacuum, Does it run fine at the begining and then start to cause problems?

Try taking the gas cap off and ride it. Just a Guess..

It sounds more like vacuume leaks, bad hoses or something.

[TIMMYDUCK]

Have you run a compression check ?

[bergs]

Did anyone read the post?


I'm curious what lack of compression, a blocked gas cap, or not running on all cylinders has anything to do with this issue?

For example, a fuel injected vehicle won't rev to 3k under any of questioned scenarios.....just sayin'.

Origin- Your issue is in the engine management electronics or a vacuum issue. Personally, I think Wishbone might have it nailed with the TPS. Another thought is the crank position sensor.

[GNTurbo6]

IACV or ECTS

[idratherberidin]

KIA=Korea's Idea of a Automobile

[TimD]

Definitely check for codes first... being obd2 it almost certainly has or will throw a code for that. Could be a big air leak. I have a logger/code reader if you need one.

[Kham]

Originally Posted by bergs

Origin- Your issue is in the engine management electronics or a vacuum issue. Personally, I think Wishbone might have it nailed with the TPS. Another thought is the crank position sensor.

if crank sensor is disconnect, car will not start. dunno about race up to 3krpm. idle not steady sounds like TPS but that would throw code. i dont know aobut while driving. gear fucked up?

[bergs]

Originally Posted by Kham

if crank sensor is disconnect, car will not start. dunno about race up to 3krpm. idle not steady sounds like TPS but that would throw code. i dont know aobut while driving. gear fucked up?

Not disconnected, faulty.

With a bad CPS, I've seen vehicles do everything from run like complete shit all the time to mis-fire once in a while to being fine for 20 feet and then crapping out....the list goes on.

[ssg]

Seems you're not the first one with this problem, I realize this is just more input but..maybe this will help:

Surging - Kia Forum

For those too lazy to click:

This is a very common problem on 1998 and newer Sportages. The issue is the electrical connectors to the TPS (Throttle Position Sensor), IAC (Idle Control Valve) and MAS (Mass Airflow Sensor). These connectors develop high resistance over time and the usual symptom is a high and uncontrolled idle...upwards of 3000 RPM, and usually NO check engine light.

The TPS is located where the intake pipe meets the throttle body. Connector facing towards front. The IAC is on the intake pipe directly over the exhaust cam. Electrical connector facing straight up. The MAS is the round plastic unit right after the air filter. Electrical connector on the backside.

The fix: You can pull off the connectors and clean them and recrimp them. This will fix it...for a while. It will come back eventually. The best fix is drastic but it fixes it permanently and it is what I did and never had the problem again. Cut off the electrical connectors and solder the wires directly to tabs on each sensor. This requires knowledge and skill in proper soldering techniques. And you also have to use a dremel to cut away part of the plastic around each sensor to gain access to the tabs. But it works.

One other thing to check. Make sure the ground wire between the battery tray and the intake manifold is in good shape. Connections clean and tight. A poor ground here will also cause wacko idle problems.

[loridin64]

throttle pos sensor
mass air flow sensor
ive seen bad 02 sensors dip the RPM's too

edit: i guess it pays to read ^^ oops