ROUGH IDLE IN GEAR THROTTLE POSITION SENSOR OR IDLE SPEED

1990 Mitsubishi Mirage

Tiny

KHLow2008

July, 21, 2012 AT 1:50 PM

Check the valve clearances.

Tiny

mhooper87

July, 22, 2012 AT 5:52 PM

Had (supposedly) valves checked and adjusted. Could this be a gas cap problem? Mine is a little rusty with some crystallization but seems ok otherwise. It is the original cap.

When I give 15 seconds of ignition w no start then crank the ICS SEEMS to recalibrate meaning I get searching rpms again. Everytime it seems to search less and less. Should I just give it a week to try and sync? Someone also mentioned programming the (new ECU) any ideas around these two issues. Thanks again.

Tiny

KHLow2008

July, 22, 2012 AT 7:41 PM

The ISC is faulty causing the problem.

Tiny

mhooper87

August, 14, 2012 AT 9:08 AM

ISC is new from mitsubishi. Only a few months old. Wandering rpms are self resolving but I am getting a little random rpm surge when stopped in gear post MAF replacement. Vibration is still a problem still rough in gear at operating temp. Something is not telling the engine to lean out? Or increase rpms? While in gear at a stop. Its almost backwards meaning out of gear no ac rpms increase and idle is smooth in gear w or w/o ac rpms increase a little but not enough? And I get a steady shake through the steering wheel - shake stops as soon as i'm out of gear. Is throttle position sensor a possibility?

Tiny

mhooper87

August, 14, 2012 AT 9:17 AM

Could use additional information on MAP location - but can not find it or any reference to it on 90 mitsu mirage.

Tiny

KHLow2008

August, 14, 2012 AT 3:04 PM

That means your vehicle is not equipped with MAP sensor.
How many mounts did you replace?
What are the idling speed under each conditions as described?

Tiny

mhooper87

August, 14, 2012 AT 3:53 PM

Mounts are maybe 3 months old. Reset idle again by ear. The car wants and does for a moment, run smooth in gear but then shaking starts and exacerbates I also hear some puffing like exhaust leak ( but had that checked )as idle lowers and shaking starts most noticeably when I first go in to gear.

Tiny

mhooper87

August, 14, 2012 AT 3:56 PM

Replaced all 3 motor mounts and 1 trans mount. 3 months ago

Tiny

mhooper87

August, 14, 2012 AT 3:56 PM

Setting idle higher doesn't seem to help.

Tiny

KHLow2008

August, 14, 2012 AT 4:02 PM

I need to know the idling ccondition. Setting it higher would cause more problem as the computer would be compensating for too low rpm and decreasing when it gets too high.

By ear? OMG, so the idling surge is by ear too?

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