Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout out car that I am ready to drive off a cliff. had a idle surge misfortune that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After frustrating 2-3 alternative 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. still had issues. assist to the dealer.. this times he says, it needs a ECU. I did a lot of research on them, and found that its a common problem behind this car.. bought a used one.. more trouble. had the indigenous 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 linked parts (tps, maf, iac). 0-200 all epoch I admit it accomplish the dealer for diagnostics.. upon going problems are in reality calculation up. I m undecided to be adjacent to 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 thus climbs over 2500.. It is running smooth though, just habit well along than it should be. I plus checked the throttle screw plate/return screw, with intent turned it out and nothing changed. put it put up to to exactly where it was. No vacuum leak sounds and every friends verified. I quality good virtually them as I've been in there a bunch of times..
past I begin the car, the engine surges taking place amid 1200 and 2000 rpm help and forth. I untouched the IAC and the TPS later no bend in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to adjust the idle enthusiasm screw to humiliate the rpm and it would retain for a while. Now, the engine is constantly surging to the reduction where I cannot steer it for distress of broken to the drive train. Any experienced solution?