Car trouble thread. Need advice.

I have a Mitsu expo sport.
4 banger, 5 speed manual.
Just a few days ago my car started acting up.
It won't idle properly.
When I first start it up it will idle at about 2000rpm.
Which is rather high for its normal idle rpm, but its cold here in NY. So thats not as much concern(unless you know something I don't).
When it finally warms up is when it starts.
It will drop to idle at 1000rpm, and then it will rev to 2000rpm, then drop to 1000, then rev to 2000.
And it will do this in neutral or with the clutch in.
It drives perfectly fine, except I notice that when I let off the gas to decelerate it does pull back harder and gear down more now.
But does anyone know why my engine revs like that?
Does it need a comlete tune up?
Havnt had that done in a long while.
Any suggestions?

 

[Wik]

Man my Ex G/F has a Galant that did some strange crap like that. I ended up buying a used throttle body for it for parts. I checked the error codes and ended up replaceing the throttle position sensor and the speed sensor I think. Do you get any error lights on the dash? Maybe you just need to replace the spark plugs and the fuel filter. 90% of the time with problems like that with no error lights it is either a fuel delivery problem or bad spark.

 

[Soybomb]

<< e throttle position sensor and the speed sensor I think. >>


I would guess one of those or an idle air motor. You might want to look around and see if you can check the codes on it yourself, I'm not familiar enough with them to tell. I don't think it needs a tuneup though, I think yhou've got a defective part.

 

Hrmm.
Nothing on the dash goes off.
The car runs fine.
Just will not sit at idle.
Hrmm.
Dont feel like paying to get it checked out.
Rough.

 

[Sluggo]

Last time I had a car do something like that, it was the Throttle Position Sensor. The trouble is it could be any one of a hundred things in the fuel or ignition system.

 

[Wingznut]

Take it from an ex-Chrysler/Mitsubishi drivability technician...

First thing, clean the inside of the throttle body, especially the backside of the throttle valve. Also be sure to clean the Idle Air Control port (a hole next to the throttle plate, about the size of a dime). You should be able to find some Throttle Body Cleaner at your local auto parts shop.

Try that and see how it goes. Don't go tuning it up, or changing spark plugs. Those definitely won't fix it.

Feel free to PM or email me, if you have any more questions.

 

If it involves removeing parts from the engine, Im rather non-equipped to do that.
I wasn't really suspecting plugs, but more ignition system.
I thought it had something to do with the throttle, since it won't idle properly.
I don't know much about it, wanted to see what you guys think it could be, cost, etc.

 

[Wingznut]

My suggestion doesn't really require moving anything. You'll just have to loosen the hose clamp for the intake hose, and remove one end from the throttle body. Just enough so you can access the inside of the throttle body.

If you end up taking it in, and they do clean the throttle body, you are looking somewhere around $130.

 

1) Clean the throttle body
2) Check for a dirty air cleaner
3) With the ignition key removed,Remove the negative battery cable and let it sit for 15 Minutes.Reinstall cable,start vehicle and drive it for at least 1/2 hr.This will erase all trouble codes in the computer.
If problem persists,either go to a dealership and have them check for trouble codes or go and buy a code reader and check them yourself.Most repair manuals today have the codes and thier respective meanings listed under Emission controls.


Good Luck

 

[Ornery]

Don't know specifically about your car, but it sounds like the &quot;low speed idle valve&quot;. Mine is controlled by a solenoid and the shaft in it can get corroded and stick. If you try to free that up do NOT use silicone based spray. I hear that can ruin an oxygen sensor instantly.

There may also be any one of a half dozen sensors that aren't working right from being clogged or sticking. The throttle position sensor is another good call. Start screwing with the cheap, easy to get at parts and work your way up. At some point you may need to take it to a mechanic. Talk to friends about their recommendations for a trustworthy one.

GOOD LUCK!

 

[casimec]

What year is the car?
Here are link to find fault codes.

http://home.san.rr.com/techweasel/articles/troublecode/mitsubishi.htm

http://www.ecutecparts.com/ccodes/mitsubishi.html

http://www.batauto.com/mitsu.html

 

[Emulex]

that car is &quot;hunting&quot; All Fuel injected cars will do that when a fault is occuring. You know how to read the codes on the car?

You do know that all fuel inject cars need to have the air cleaner, and throttle-body and Mass air flow cleaned with fuel-inject(carb spray) cleaner on a regular basis?

Idle air control valves and the like at right there in the intake, same with PCV vales.

Boy people sometimes just don't take care of their cars and wonder why they act funny!

You should spenda bout an hour a month on your car, in maintenance or pay someone to do it. It will run to 250K miles if you take Really good care of it

 

Nice suggestions.

Well Im currently OVER 250K.

Its a 92. Still going strong.

As I said before, I don't work on cars, so I would NEVER take a hour a month working on it.
I would not know what a throttle body is, what it looks like, where its located.



<< You do know that all fuel inject cars need to have the air cleaner, and throttle-body and Mass air flow cleaned with fuel-inject(carb spray) >>


That seems to be the general info im getting from research.
Im trying to find specific info on my car now.

Im going to get a chilton's book specifically for my car.
Id like to be able to take care of stuff like this myself.
The car I have is a Mitsubishi 1992 Expo sport LRV. 5spd manual.
Thanks for the suggestions.