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2000 LS400 Crazy Idle Issues After Starter Replacement

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2000 LS400 Crazy Idle Issues After Starter Replacement

Old 05-28-17, 05:14 PM
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Default 2000 LS400 Crazy Idle Issues After Starter Replacement

So recently I replaced the starter on my Ls400, since then, I just cannot get the car to run/idle right. The car is either showing a misfire in every cylidner and idling like junk, usually lower than it should, but revs and runs half decent, or throwing a p1220 and p1228 code and the idle control valve acts up, I feel like this MIGHT be unrelated and just a loose connection but it is worth noting. When I unplug the MAF sensor, I can get the car to idle right but it won't rev past 3k without breaking up, that is, if it starts up without the MAF plugged in, which usually does work unless the idle control valve is acting up. No matter what I change up or what I do, I am stuck with one of these 3 issues.I am completely stumped at this point, I checked every vacuum line and made sure it was connected, every plug seems to be plugged in correctly. Unless I mixed up a vacuum line somewhere or just missed something very obvious, I am all out of ideas. Any ideas or help would be greatly appreciated
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Old 05-29-17, 01:00 AM
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I would guess that you nicked one of the wires for the sensors while removing the tb and other stuff to get to the starter.
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Old 05-30-17, 12:41 PM
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you will have to retrace your steps and triple check to make sure every wire and vacuum line is in their proper order or location or undamaged. it is very likely something was damaged or reinstalled improperly during the removal of the intake manifold.
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Old 05-30-17, 04:56 PM
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Unless you have extremely low mileage, then just about every plastic connector housing that you disconnected is brittle and has lost its latching lance..

Harness side connectors include the spark plug coils, the fuel injectors...had to replace 7 out of 8 (all the dealer had in stock was 7) the oil control valves, throttle body motor and position control, the ECT sensor, VSV's, and others...

Did you tighten the clamps on the intake at throttle body...is the rubber seal correctly seated?

On these cars, if original connectors (1995+ especially), then expect to replace the shells...not splice a new one in, but compress the contact pin lances, remove from the old shell( or if brittle enough, simply and carefully break it away with an appropriate tool so as not to mess up the contact pin, and reinsert into replacement.

the P.N.'s are on the shell itself and readily available from Lexus
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Old 06-01-17, 02:28 PM
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pirate air leak or throttle body harness would be where I look. No idle control valve on '98+ LS400s, the throttle body controls idle speed.

Check the lines themselves for cracks too. If the idle is lumpy it's 99% a vacuum leak.
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