Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super announce car that I am ready to steer 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 frustrating 2-3 stand-in 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. nevertheless had issues. incite 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 problem bearing in mind 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 obsession to be re-adjusted? The master tech did every sorts of diagnostics upon all related parts (tps, maf, iac). 0-200 every epoch I agree to it realize the dealer for diagnostics.. on going problems are really calculation up. I m unsure to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car going on this morning, it starts happening and runs at 1750 and within a minute or hence climbs exceeding 2500.. It is giving out mild though, just quirk higher than it should be. I also checked the throttle screw plate/return screw, with intent turned it out and nothing changed. put it encourage to exactly where it was. No vacuum leak sounds and all friends verified. I setting good roughly them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF related it is lonesome measuring the ventilate that is getting similar to the MAF, hence if the intake manifold is sucking in air the expose to fuel ratio will be completely 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 spray in the place of the hissing like the engine supervision and subsequently you hear the engine stall or rev far ahead there is the leak ,could be a bad vacuum hose bad gasket on the manifold.