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Toyota Repair/2005 Scion Xb Rough Idle when I gear


Ricko wrote at 2008-07-10 18:36:22
Don't believe everything you hear! Too many Xperts out there! Ok, here's the deal. I have a Scion 2005 xb and a 2006 xb. To set up the idle, just look near the front of your engine close to the radiator fan. As you are facing the car with the hood up, near the right side of the engine, you should see the thin metal wire that gives your car gas when you depress the gas pedal. Have someone press the gas pedal quickly and you will see it move(even if the engine is off). Don't let them hold it down! Just a quick press/release or two. (You can also do this yourself if necessary, by pushing the small plastic wheel the cable rides on). Ok, after you locate the wire and the round plastic piece, locate the small nut that has a small "allen wrench" type screw in the center of it. You may see a small dot of yellow paint from the factory which shows the original location of the screw. FIRST, with a 5/16 or (equivalent millimeter) wrench, loosen the nut only slightly. SECOND, with a very small #2 size allen wrench, slightly TIGHTEN the screw until the rough idle smooths out(about 10 or 11 rpm's on the gauge inside on your odometer). DONE! Takes about 5 minutes and saves $$$ and time at the dealer!

You should have someone running the car to do this...BUT for safety reasons, be very careful not to get your hands near the fan which WILL PROBABLY COME ON!!!! And don't let someone depress and release the gas pedal while your hands are near the wire! You only need to tighten the allen screw about a half turn. After adjusting, give a quick depress of the gas pedal again to make sure it adjusts properly and seats. Remember, the higher you set the idle, the more gas you use and the quicker you overheat.  So, set it at the very minimum that takes out the roughness(between 9 & 10 rpm's is ideal). Good luck, Ricko, New Smyrna Beach, FL

Ricko wrote at 2008-07-16 19:03:56
The idle is easily adjustable with a #2 allen wrench and a 5/16" or mm equivalent wrench. Simply locate the screw near the front driver side of the engine. It's close to the radiator fan. Loosen the nut and tighten the allen screw slightly. Have the engine running so you can hear/see the engine idle as you adjust the screw. Good luck

Larry wrote at 2008-10-05 23:10:50
I have the same issue with my 2005 XA.  I do NOT believe it is motor-mount related.  I think, rather, that is is strictly a function of engine movement at idle rpm and a poorly designed air box system.  

The air-box sits a substantial distance from its support structure thus allowing the entire piece to build up a movement with the slow (idle) beat of the engine.

Attaching a bungie cord to the support bracket and the other end to the frame will dampen the vibration.

There is an idle speed adjuster right by the throttle cable end.  It has a lock nut and a center stem that turns to raise or lower the idle speed.

If you raise the idle to 800 rpm or above, the air-box stops its annoying, rattling shake.

This was a design flaw from the manufacturer and I have not seen any factory fix published anywhere.

Chris wrote at 2009-07-31 16:25:24
Hi.  I have a 2006 Scion XA with the same problem.  It idles rougly when the gear is in drive and you have the brake applied.  Once you apply gas, the engine runs smoother minus the rattling noise.

I'm brining it to the dealer today to see if it's an engine mount.  The car has 80,000 on it so I wouldn't be suprised if something broke apart.

mattl wrote at 2009-08-15 02:18:57
i have an 05 xb with 80,000 and i have had a rough idle problem that i cant figure out, i have check mounts, vacuum leak, pcv valve, new battery, plugs, air filter,

i know its more than just the air box mounting, cuz it idles so rough, especially stopped in gear with a/c on.   

im thinking it has somthing to do with cam timing sensor or fuel injectors or spark??

anybody got anything for me?



Ric wrote at 2011-01-21 19:41:56
Make sure the two tabs on the rear of the top air filter housing are secured into their mounting slots. If the top of the housing is removed to inspect/replace the filter, the tabs may come out of the lower housing and and allow it to rattle when the front clamps are secured again.

Mir wrote at 2014-01-04 21:03:39
Very nice post. My mom's xA has had this issue since the serpentine belt change, about 30K mi. ago.

First thing I made sure that air box cover was covering the air filter completely because it's a poor air box design. With the filter installed the top does not sit in all the way when you look at the back part of the cover (there are no clips there just two hinges). After pinching the top on each hinge and pushing towards hinges each side went in.

But this did not fix the low idle and followed this write-up to adjust it.

Word of advice: DO NOT USE a simple/small L shaped allen wrench to adjust the nut, I think I cracked mine a bit since it sits at an angle. So I used a 8 mm socket to loosen the nut then made adjustments using the allen wrench.

Handy Andy wrote at 2014-08-29 17:09:59
I too, have had idle speed issues and have found several ways to help you determine EXPECTED idle speed and the ACTUAL idle speed. Both require tools and both can be at least checked simply by using a SHORTING JUMPER on the DTC connector.

First - locate your DTC [Diagnostic Trouble Code Connector] - in an xA it's located behind and underneath the plastic trim by your Dash-illumination and Fusebox panel cover - to it's right and just below - behind the trim.

Using a paper clip, the DTC connector has a lot of empty holes and some filled with connection points. You see the entire length and two rows - near the middle [Pins 4,5 and one below them] are not empty and have connector pins in them - the one to the left of the twins in the center of the top row is SENSOR ground and can be used to determine actual idle speed which the Throttle Position Sensor is set for [TPS] - the bottom one is Vehicle Ground - and the other top one on the right is Sensor Ground for the SRS and ABS systems.

Taking your paper clip - snip off a nice little "U" off of the clip that can fit into the top row connectors and bottom row connector - there's your service tool shorting jumper.

Acquire an Allen wrench, and 8mm Box-end wrench and you may need to "break the seal" by using an 8mm socket and ratchet to loosen the hex set-screw. Once loosened it can be retightened and easily stay put using the smaller profile box-end wrench.

Warm up vehicle and note the idle speed [in park - set brake if M/T] and all accessories off. then put shorting jumper into left pin [#4] and bottom [11] and idle speed with go up for a moment as it enters into a test mode - note the "lights" on the dashboard at this time too - some may flash a code - don't worry. Give the engine 30-seconds to do this "test" and it'll settle down and possibly even stall due to the nature of the condition - if it stalls turn off the vehicle - the throttle body needs to be removed and cleaned - its plugged and its IAC valve may be completely blocked or stuck closed with dirt. Else if it still runs note the speed, lower than initial idle speed? Clean Throttle body and re-perform this test. Speed higher than initial? the vehicles EXPECTED idle speed signal from the Throttle Position Sensor is too high [throttle angle needs to be between 8 degrees and 26 degrees for the Sensor to show throttle at idle or low -off-idle] and may be due to a plugged throttle body port - either EVAP or IAC - and throttle may be stuck open due to dirt or object trapped in the plate - keeping it open and causing a lean condition. In any rough idle condition in high-mileage vehicles - the throttle body will need to be removed from vehicle, inspected, cleaned, adjusted [maybe] and re-installed with a new gasket. The technique I described above if to determine, the you fix then you can re-set speed easily by using the technique above by loosening locknut turn setscrew using Allen wrench to proper idle speed as shown on dash [pretty accurate 700RPM basically with all accessories off in park] and perform an INITIALIZE procedure that you do when you need to turn off the Maintenance reminder light [set to ODO - turn off engine allow to cool - press and hold reset switch in - insert key - turn to ignition [not start] and watch display turn mileage to dashes, zeroes then normal - miles. Enjoy your vehicle.

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