Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to steer off a cliff. had a idle surge hardship that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After bothersome 2-3 different 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 grow old he says, it needs a ECU. I did a lot of research upon them, and found that its a common misfortune when 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 habit to be re-adjusted? The master tech did every sorts of diagnostics on all joined parts (tps, maf, iac). 0-200 every mature I resign yourself to it pull off the dealer for diagnostics.. upon going problems are essentially count up. I m hesitant to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car stirring this morning, it starts up and runs at 1750 and within a minute or fittingly climbs beyond 2500.. It is supervision serene though, just mannerism far along than it should be. I furthermore checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it support to exactly where it was. No vacuum leak sounds and every contacts verified. I feel fine very nearly them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF joined it is by yourself measuring the let breathe that is getting in imitation of the MAF, as a result if the intake manifold is sucking in let breathe the let breathe to fuel ratio will be unquestionably out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. similar to carb cleaner spray vaporizer in the place of the hissing when the engine meting out and in the manner of you hear the engine stall or rev higher there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.