Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super push car that I am ready to steer off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After aggravating 2-3 alternating 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. help to the dealer.. this mature he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem in the same way as 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 need to be re-adjusted? The master tech did every sorts of diagnostics on all united parts (tps, maf, iac). 0-200 every times I take it complete the dealer for diagnostics.. on going problems are essentially adding together up. I m unsure to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car stirring this morning, it starts happening and runs at 1750 and within a minute or fittingly climbs exceeding 2500.. It is dispensation mild though, just showing off difficult than it should be. I furthermore checked the throttle screw plate/return screw, purposefully turned it out and nothing changed. put it incite to exactly where it was. No vacuum leak sounds and every contacts verified. I air fine approximately them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF related it is solitary measuring the ventilate that is getting in imitation of the MAF, in view of that if the intake manifold is sucking in let breathe the air to fuel ratio will be very out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. with carb cleaner spray can spray can in the area of the hissing past the engine processing and in the manner of you hear the engine stall or rev far ahead there is the leak ,could be a bad vacuum hose bad gasket on the manifold.