That's the thing...it should go down after the steering return back to default position(straight). But mine just won't or it take more than 10 sec. It's eating my fuel alot and I guess I'll stop playing with the mivec mapping with my s1 to make a loopy idle.


1. Throttle body - already clean all the carbon inside
2. Throttle cable - checked and no problem, just nice not tight not loose
3. IACV
4. Clutch slipped? - tested with 5th gear full gas on 50 mph and the rpm goes up slowly follow by the engine tone.
5. Spark plug?? - checked and no problem
6. o2 sensor
7. CEL - no cel so far
8. Isc

Added 27/8/2011
Once after clean the TB, is still the same, and the rpm will hold at 2k even longer. So, we adjusted the idling through BISS and also the throttle cable in the same time, and now it seems to minimize the problem, but it still occur, very seldom compared last time.

 

bump.

This is happening to me.

Cold start=2k

Highway driving is fine
Neighborhood driving = 1.1k idle in drive, 2k+ in park idle

Replaced entire throttle body.

Is there any way that it could be the coolant temp sensor?

 

You sure your throttle cable isnt sticking? Have you tried to adjust it some? try making it to where it has a slight amount of play before the pedal engages it.

 

How do I loosen the throttle cable?

 

loosen the bolts that hold the throttle cable to the manifold

 

My throttle cable was routed right on top of the engine block. I removed the intake hose (the large one between the airflow sensor and the TB) and routed it in the back of the engine compartment. Hopefully that fixes the issue. If not, I'll try adding some slack to the throttle line.

I've heard that the housing of the cable gets hot and sticks to the line, so maybe that's why it revs up in neighborhoods.

 

This is especially prominent with aftermarket headers/manifolds as no heat shield allows all that heat to go straight up to the cable. However everytime my rpms did this with higher idle it was due to my cable being too tight. I would always try to keep the cable taut when I adjusted it but came to realize you need to have some slack in there to be sure its going to allow the throttle's return spring to properly retract the throttle plate all the way.

 

I drove around for a while and the rpms went up. I got out and popped the hood. When I pulled some slack in the throttle cable, the rpms returned to normal. Does that mean it's the cable?

Also, when I pulled the slack and let it sit, the rpms gradually rose again until i pulled some more slack in the line. I'm guessing thats the TPS that does that?

The line seems really sensitive to movement, so I don't know if it got knocked loose or what, but when I rerouted it, the rpms went up to 3k, so I had to put it back on top of the block.

Btw, thanks for the quick responses. It's been doing this for a while, and I assumed it was a sensor until I bolted a new throttle body on last week.

 

Sounds like you need a new Throttle Positioning Sensor. I had the exact same problem in my mustang. You can take a safety pin and pierce the wire and check the voltage with a multimeter, but I'm not sure the voltage range for a lancer. The 5.0 fox stang is .98-1.15 or so, and I was over 2.3 volts. I would just replace it and see if that fixes the problem, it should be less than $20. Before you go out and buy the sensor, check for a vacuum leak. just listen under the hood, and you get take starting fluid and spray around under the hood while running and see if the idle jumps up anywhere. hope this helps

 

When you replaced the TB did you put on a whole new assembly? (new sensors included) or just another throttle body and put all your old stuff on it?

 

I replaced all of the sensors.

The throttle cable has frayed through the throttle cable housing in two spots. The cable is also covered in carbon by the throttle switch.

Like I said before, it only revs up after I've driven the car for a while. There is no check engine light on, so I don't think it's a sensor.

I ran a smoke machine, and there was no leaks. Newer sensors. I'm taking it to the shop tomorrow, so I'll update you guys.

 

The shop said it was the throttle cable, but I drove home and it's still revving past 2k rpms in park.

I'm taking it back to the shop. I guess I'll update again tomorrow.

Sigh....

 

So then they replaced your cable and still revvs? Did you try to adjust it yourself with the new cable? I've learned just because they have a shop doesnt mean they know what there doing lol.

 

I think they had to reroute the cable because it was getting caught. They will fix it tomorrow, hopefully.

Is there any way a cracked radiator would affect the idle?

 

Nope not the way your describing it