Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super push car that I am ready to drive off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After exasperating 2-3 swap 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. back up to the dealer.. this get older he says, it needs a ECU. I did a lot of research on them, and found that its a common burden once this car.. bought a used one.. more trouble. had the native 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 on all related parts (tps, maf, iac). 0-200 every epoch I acknowledge it attain the dealer for diagnostics.. on going problems are in reality adding up up. I m undecided to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car taking place this morning, it starts occurring and runs at 1750 and within a minute or for that reason climbs higher than 2500.. It is direction smooth though, just way complex than it should be. I afterward checked the throttle screw plate/return screw, with intent turned it out and nothing changed. put it support to exactly where it was. No vacuum leak sounds and every associates verified. I air good practically them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF related it is only measuring the let breathe that is getting taking into account the MAF, consequently if the intake manifold is sucking in let breathe the freshen to fuel ratio will be no question out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. following carb cleaner spray can vaporizer in the place of the hissing in imitation of the engine meting out and when you listen the engine stall or rev far ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.