Throttle Control Motor

[BGS300]

My 1998 GS300, 190,000 miles just started bucking and almost stalling out at idle or when I start to slow down to stop. Code P1128 says throttle control motor malfunction or lock. Has anyone had xperience with this? I want to check the TCM with an Ohm meter but there are too many wires and I have no mechanics manual for this. Otherwise i will just replce the unit and hope for the best.

sidenote: all of this started after the front left lower ball joint went out and was replaced.

[1990LS400]

http://www.toyodiy.com shows the part number for the "MOTOR, THROTTLE CONTROL" for the 98 GS300 as 89672-30020. Looking up the part number on http://www.parts.com shows a discounted price of $202.95 . The description for the part number of parts.com says "Idle speed control, gs300" -- odd that the description is so different.

[ja73]

http://www.toyodiy.com shows the part number for the "MOTOR, THROTTLE CONTROL" for the 98 GS300 as 89672-30020. Looking up the part number on http://www.parts.com shows a discounted price of $202.95 . The description for the part number of parts.com says "Idle speed control, gs300" -- odd that the description is so different.

I've heard that it can just be a dirty throttle body,(TPS) or throttle position sensor got that term from dealer same as idle speed sensor having same problem as you (98 GS400) a certified lexus mechanic told me to clean the throttle body with a carb & throttle body cleaner first butterflies inside throttle body could be sticking and remove and clean throttle position sensor to save yourself some money while your at it get some M.A.F sensor cleaner to M.A.F stands for mass air flow sensor read the directions very carefully for the air flow sensor cleaner look were the wires hook up to the air sensor right after breather filter if the sensor brand is karmen vortex don't use warns on back of can!

[DaSwede_420]

sidenote: all of this started after the front left lower ball joint went out and was replaced.

What noise did it make when ball joint went out?? was it a pop when turning?

[bluegs]

My 2000 GS400 had CEL and VSC warning lights with code 1128 and a rough idle. I cleaned the MAF sensor but it made no difference. After I took the engine cover off, I found a broken vacuum hose, which I repaired.

When I started the car, the RPMs were high, so I turned off the key and started up again. This time, everything was normal and it's been fine ever since. The car has 177,500 miles but the engine runs like new again - smooth, quiet and powerful.

This is another example of just how ambiguous and misleading the diagnostic codes can be, usually with costly consequences to the owner. My car has not been at a dealer since 60,000 miles and it's running great. I recently had the timing belt/tensioner/idler pulley/watt pump pump replaced (first time, not by the dealer) which also made a difference.