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fluctauting rpms

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well by boat is still messed up the dealer didnt fix it. the ecu flashing is fixed and all the guages are working ,but the rps fluctuate from 400-1100 in idle. sometimes under speed it will try and die out and pick back up real quick. i wish i didnt have to wait until the dealer can fit me in again. its been a month and no boat. i tried disonnecting the perfect pass thinking it maybe sending weird signal but that didnt work. i aslo disconnected the mmdc box, and that didnt work. anyone have any ideas? anything? i dont want to wait another 2 weeks.

on another note i did find a small wire on the front right side of the motor with a tiny sized rubber housing simaler to a spark connector not connected to anything. i cant seem to find where it would connect to ? its a light tan color and about the size of a speaker wire. anyone know what this goes too??

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The tan wire is never connected on the monsoon. It must be used on a different motor. They use the same harness for all motors.

There are a few things that I can think of that would cause the RPM problem. Your MMDC will make no differance in the engine, its a one way signal from the sensors. Start checking ground wires (big one on the starter!!!) even the battery connections, clean and tight. Under the dash near the throttle there is a whole buss bar of grounds mostly for dash stuff, but the big ones are part of the ground circuit.

Does the fuel pump change sounds when this is happening? That would indicate bad fuel(somehow you may have gotten water in the fuel), bad fuel pump, bad fuel filter, bad fuel pressure regulator.

The other may be a bad ECM. It doesn't sound like it, but you never know. Any friends with an 04' - 05' monsoon that you could swap ECM's with???

Have them hook it to there DIACOM and check for trouble codes. Have they done a fuel pressure test?

I sure wish you got better service. I hate it when Malibu looks bad because of crappy service.

Bad gas is what it sounds like, stop with the mexican food. Biggrin.gif


Edited by maliboo

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