Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to steer off a cliff. had a idle surge pain that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After aggravating 2-3 interchange used IAC s, I took it to the master tech at lexus. He said it was the IAC valve. He tried my used ones.. and finally a rebuilt one. yet had issues. back up to the dealer.. this period he says, it needs a ECU. I did a lot of research upon them, and found that its a common misery in the same way as this car.. bought a used one.. more trouble. had the original one rebuilt by a specialist.. and that s where I am at now.. Put it in tonight and the car idles at 2k rpm. Does the TPS dependence to be re-adjusted? The master tech did every sorts of diagnostics upon every united parts (tps, maf, iac). 0-200 every era I endure it get the dealer for diagnostics.. on going problems are really surcharge up. I m undecided to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car in the works this morning, it starts happening and runs at 1750 and within a minute or appropriately climbs on top of 2500.. It is dealing out serene though, just showing off forward-looking than it should be. I after that checked the throttle screw plate/return screw, with intent turned it out and nothing changed. put it urge on to exactly where it was. No vacuum leak sounds and every contacts verified. I character fine more or less them as I've been in there a bunch of times..
next I start the car, the engine surges up amongst 1200 and 2000 rpm back and forth. I misused the IAC and the TPS once no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to acclimatize the idle swiftness screw to lower the rpm and it would preserve for a while. Now, the engine is at all times surging to the narrowing where I cannot steer it for terrify of broken to the steer train. Any experienced solution?