Vibration When Stopped

Is the AC on, does the vibration stop with the ac off? How bad is the vibration, is it truely bad or just noticeable? If the vibration comes and goes every few seconds it leads me to believe it is ac related and only happens when the ac cycles. If it goes away when you turn off the ac AND the vibration is not bad do this.

Pop the hood and watch your engine and note when the vibration happens. If it only happens when the compressor cycles on and then goes away whithin a few seconds then your vibration is probably just due to the extra engine strain of the compressor and you are noticeing the time gap of the compressor engaugeing and the ECU compensateing the idle RPM to accomidate this.

The reason it may feel it is from the drivers side is the engine vibration may be transmittting up through the engine cradle makeing you believe the problem is on the drivers side. But the transmission is on the drivers side of your vehicle and I have a very hard time thinking you have a problem with a new auto tranny.

While I was at work today I did a bit of research.

The idle speed for the xb completely warmed up, all accessories off, cooling fan off and vehicle in park / neutral is 700rpm +/- 50.

There are several things that could cause poor idle. A small list of things would be.

1. Faulty Mass Airflow Meter
2. Clogged / faulty fuel injector.
3. Faulty IAC valve.
4. ECU calibration
5. Faulty O2 or A/F sensors

However Id bet against any of these things for a few reasons.

1. Your check engine light is not on. Even if the ECU did not detect an actual bad part, the light would probably still come on because the A/F sensor would be detecting a lean / rich condition.

2. If any of these problems were present you would probably be noticeing poor engine prefrmance when driving or poor fuel economy. And it is my understanding that the vehicles drive ok and the problems are only at idle.

3. I am a completely sold on Toyota / Honda initial quality and I just do not see too many faulty new parts, it does happen but not that often.

I think the problem is in an adjustment somewhere or maby possibly even a loose motor mount not secureing the engine properly.

However I did find one thing that may be of help. Im going to type this exactally as the TSB is written. I know were talking about a auto tranny vehicle and both vehicles are '05 but the process still outlines throttle cable adjustment and the symptoms are kinda the same.

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TSB EG012-04
Model's - '04 Scion xA and Scion xB with Manual Transmission
Title - Intermittent Rough Idle or Low Engine Idle at a stop.

Introduction: A small number of 2004 model year Scion xA and Scion xB vehicles equiped with manual transmissions may experience an intermittant rough or low engine idle at a stop due to a possible misadjusted throttle cable.

Applicable vehicles: All Scion xA and Scion xB vehicle equipped with manual transmissions produced BEFORE the following VIN's.

Scion xA - JTKKT6*4*40074070
Scion xB - JTLKT3*4*40165000

Repair Procedure:

1. Carefuly hold the Throttle Plate closed, while holding the Throttle Plate closed push the exposed throttle cable back towards the cable housing to remove any possible slack.

2. Measure throttle cable freeplay by measureing how much cable comes out of the cable casing when pulling the cable towards the Throttle Body.

Standard Range 1mm - 3mm

3. If cable freeplay is not within standard range adjust throttle cable freeplay

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I think you are correct that your idle is too low. An easy way to tell is this.

Inspect the area around the throttle plate untill you find a adjusting screw in the throttle linkage area that the closed throttle linkage rests against, it will probably have a yellow or pink paint mark on it.

Place something thin like a pocket screwdriver blade or thin piece of cardboard between this screw and teh throttle linkage to bump the idle up a bit and hold it steady.

Play around with it untill you get your RPM's holding steady at 700 +/- 50 then see how the vehicle idles. Make sure to turn ac on and off to make sure all is good.

If everything is running smooth then there is your problem. You can loosen the lock nut on the adjusting screw and turn it in yourself if you want too. But be forewarned that the paint mark is there as kind of a anti-tamper mark to show if someone has been jacking with it, but I dont now of anyone actually paying any attention to it.