atcfixer

iTrader: (1)

I know this isn't exactly a Lexus forum, but it's still toyota and there's plenty of swaps. Anyway, it's in a 1990 LS400 w\o traction control. Cold start idle is normal, and if I let it sit and warm up, it idles down when worm like normal. When I drive it, most of the time the next stop I get to the idle is high. If I sit there for about 20-30 seconds, the idle comes back down to what it should be. Seems the IAC is working fine, but for some reason the ECU is running it high while driving, or it's lagging behind after the throttle is let off. On slick roads it's enough to effect braking where the front tires lock up and the rear tires are under enough power to still push the car straight. I normally coast in neutral to stops for better mpg (drove my corolla 80k miles that way no problem).

While driving, the idle is high enough to self drive about 35-40mph if I just let off the gas and let it coast down in gear and never slows down any more. If I brake down to say 30mph, it maintains 30mph on it's own. Resetting the ECU seems to make it function normally for a short while. I also have two parts cars 93 and 94. Basically have the fair average cost of one LS400 into all 3 and all 3 run/drive, just one wrecked (rear ended) and the other has no title.





Little more info on it's story, probably not related if you want to skip.

The power steering idle kick up valve is back and sucks power steering, currently driving it w\o power steering till I can get a chance to pull it and plug it and run a bypass vacuum hose. The power steering fluid was sucked in the intake between the mas and throttle plate.

Also the car has been neglected for probably 25 years on repairs which is why I got it cheap. There is no check engine light and besides the idle it runs great. After the power steering is fixed I plan to do a tune up (OEM plugs & wires) and replace the coolant temp sensor (gauge sensor is wacked) and the coolant temp sender since I'll be in the general area and it's pretty cheap. Antilock brake light is on, fuse isn't pulled, but haven't looked into the sensors to see if one of the wires is ripped apart.

Right before I bought the car, it had a new starter installed, new tires, and ball joints, $1500 repair bill and I got the car cheaper than that =). I have to install rear wheel bearings yet and source an OEM radio for it, the aftermarket junk unit they had was a high draw on the battery (~70ma just for the radio).

Thanks for any input. I have the EWD for the car, but no repair manual yet. I can't seem to find someone else with the same situation, most others describe a stuck IAC.