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Hey Everyone,

I have a strange problem and i am scraching my head now, not knowing what is going on.

I had a while back SES light on, which had the code P0135 & P0134, The Oxygen Sensor code. i have since then replaced the oxygen sensor and reset the ECU. Now before i did any changes my car had a high idle, very high, to exact at around 2K. Anyway after replacing the O2 sensor and clearing the ECU the car runs flawless, no hesitation, no sputtering nothing, the only thing i have now is that i have a very high idle. The cars isn't trowing any codes are anything. What do you guys recommend me checking or doing next?


THX

R


Ps. 2.4L with no mods other then a short ram intake
Clean the throttle body, idle control valve with throttle body cleaner along with a can of SEA Foam or Cataclean. After cleaning the idle control valve you will need to unplug the negative cable to the battery for five hours and reset the idle in the vehicle because the ECU has to relearn the RPM of the motor while it is running. If you can manually move the throttle control on the throttle body than most likely it is a dirty idle contol valve. If the RPMs bonce up and down than replace the trottle position sensor.
 

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2001 Spyder GT
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My 01 Spyder Gt has the same issue... Disconnecting the mass sensor the car will idle normally... Keeping my eye on this one hoping you find a cure.
 

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My 01 Spyder Gt has the same issue... Disconnecting the mass sensor the car will idle normally... Keeping my eye on this one hoping you find a cure.
When the MAF sensor is disconnected there should be a change in how the vehicle runs, so clean the MAF with mass flow cleaner and this should affect the parformance of the vehilcle. I had to use a Snap On ODB II reader to check my MAF was working within factory specs because this sensor needs to read and report the air volume correctly to the ECM for the vehicle to idle at 1000 RPMs after warming up three to four times.
 

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2001 Spyder GT
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In my case I have a new Maf because the garage told me that was my problem...then they told me it was the throttle position sensor.. Then they said it was the iac… Obviously they are just guessing at my expense… No one in this town know anything about the Mitsubishi... I went to the dodge dealer, and they told me to go to Mitsubishi… so I said okay… I have a 2001 Chrysler Sebring LXi... he said .. Bring it in… The kid did not even know Chrysler was part of Mitsubishi...I’m hoping someone here figures this out, so I will stay tuned to this post.
 

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In my case I have a new Maf because the garage told me that was my problem...then they told me it was the throttle position sensor.. Then they said it was the iac… Obviously they are just guessing at my expense… No one in this town know anything about the Mitsubishi... I went to the dodge dealer, and they told me to go to Mitsubishi… so I said okay… I have a 2001 Chrysler Sebring LXi... he said .. Bring it in… The kid did not even know Chrysler was part of Mitsubishi...I’m hoping someone here figures this out, so I will stay tuned to this post.
The mechanics are going down the PO300 misfire checklist to fix the high idle problem and left out the EGR valve remaining in the open or closed position, which will cause high idle issues along with poor fuel mileage. Only certified Mitsubishi mechanics understand how these motors run correctly or someone who has worked on them regularly. Hope this helps solve the problem.
 

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In my case I have a new Maf because the garage told me that was my problem...then they told me it was the throttle position sensor.. Then they said it was the iac… Obviously they are just guessing at my expense… No one in this town know anything about the Mitsubishi... I went to the dodge dealer, and they told me to go to Mitsubishi… so I said okay… I have a 2001 Chrysler Sebring LXi... he said .. Bring it in… The kid did not even know Chrysler was part of Mitsubishi...I’m hoping someone here figures this out, so I will stay tuned to this post.
Wheel Tire Plant Automotive tire Product
 

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@Widgmaster
If you want to poke around your high idle issue yourself let the engine get to full warmed up temp where the idle should be down around 750-650 get a fire extinguisher and some cans of carb cleaner and spray around the air intake after the throttle body and around the rhrottle body in short bursts waiting about a minute after each spray for the cleaner to dissipate. If you hit an air leak that affects how the engine idles the engine idle with noticeably change when it sucks in cleaner since it changes the fuel/air mixture like choking a carb. To adjust the idle screw you're supposed to use a scan tool to halt the idle speed motor at a specific position, otherwise the computer will be trying to adjust idle while you're turning the idle adjust screw. A shop with a higher end scan tool like a Snap-on Verus, Modis, Zeus, Apollo, etc should be able to perform that function and allow idle adjustment with the screw. However since that screw is changing the amount of air bypassing the throttle plate it's somewhat of a bandaid against something else wearing or getting dirty and adjustment will probably need to be made again. I'd find the source of the issue. We've seen wear in throttle linkages and throttle stop screws that allow the plate to close more than normal and of course the usual dirty throttle and dirty IAC issues. May not be a bad idea to pull the throttle body off and clean it out thoroughly then install with fresh gasket. If it's a low idle it's likely just dirt build up or parts wearing closer together, if it's a high idle it's probably an air leak. One more thing that can throw idle all screwy is bad coolant temp data, that may be worth looking at too.
 

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2001 Spyder GT
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Thanks for the post Bitter... I was warned by a few fellows not to touch anything if you don't know what you're doing and that's me in a nutshell. Give me a Chevy block in parts and I can put it together but these Mitsubishi engines got me stumped. The fellow at my local garage thinks he knows, but he just makes guesses, and it's costing me an arm and a leg. I already sprayed quick start all around the vacuum lines and the engine did not rev up like I was told it would do. You may be onto something with the temp sender ... Pecker head at the garage was turning the biss screw back and forth like he knew what he was doing… I read on here there is a method to dialing in the biss screw, so he probably messed that up too. I got too much money tied up in this car to be playing around with it. I think I will bite the bullet and take it to my authorized Mitsubishi dealer in London Ontario when I get it out this spring. I have new temp sensors and a new thermostat I will have them install also. I found a Canadian dealer where I can buy a new biss screw with the o-ring and cap.
 

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The screw and o-ring are probably fine, but adjusting it while NOT in the special service mode will screw up it's set point and confuse the computer more. Be sure to spray around the throttle body, the shaft area especially. Used to see people saying the throttle shaft seals and bushings were leaky on these cars but that may have been under boost not normal engine vacuum. Don't forget to also spray around anywhere a gasket seals things together around the intake, not just vacuum hoses. A broken and leaking gasket will let air suck through too. Also there's some lines under the manifold that can be food for mice, could be as simple as something under/behind you can't see that's been chewed through.
 

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2001 Spyder GT
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My biss screw seems to be very loose. After being at the garage the biss screw can be turned with very little effort...like it's broken or something. I should be able to turn that till it comes out, right. Mine turns and turns and turns and you get the picture. That must be my fast idle..... maybe I should have the throttle body rebuilt or buy a new one?
 

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A good used or rebuilt throttle body probably isn't a bad idea. Still need a dealer or someone with a capable scanner to set the idle speed though.

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