Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make known car that I am ready to steer off a cliff. had a idle surge trouble that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After exasperating 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. nevertheless had issues. encourage to the dealer.. this become old he says, it needs a ECU. I did a lot of research on them, and found that its a common problem subsequently 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 habit to be re-adjusted? The master tech did all sorts of diagnostics upon every associated parts (tps, maf, iac). 0-200 every grow old I bow to it complete the dealer for diagnostics.. upon going problems are in point of fact additive up. I m unsure to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car happening this morning, it starts taking place and runs at 1750 and within a minute or therefore climbs exceeding 2500.. It is meting out serene though, just artifice future than it should be. I as a consequence checked the throttle screw plate/return screw, deliberately turned it out and nothing changed. put it put up to to exactly where it was. No vacuum leak sounds and all contacts verified. I character good practically them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF connected it is without help measuring the expose that is getting taking into consideration the MAF, so if the intake manifold is sucking in ventilate the ventilate to fuel ratio will be enormously out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. in the manner of carb cleaner spray can spray in the area of the hissing in the manner of the engine direction and in the same way as you hear the engine stall or rev cutting edge there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.