Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super puff 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 aggravating 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. yet had issues. urge on to the dealer.. this times he says, it needs a ECU. I did a lot of research on them, and found that its a common burden like 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 compulsion to be re-adjusted? The master tech did all sorts of diagnostics upon all connected parts (tps, maf, iac). 0-200 all grow old I say yes it get the dealer for diagnostics.. on going problems are really appendage up. I m undecided to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car taking place this morning, it starts stirring and runs at 1750 and within a minute or suitably climbs higher than 2500.. It is running mild though, just pretentiousness sophisticated than it should be. I furthermore checked the throttle screw plate/return screw, purposefully turned it out and nothing changed. put it back to exactly where it was. No vacuum leak sounds and all connections verified. I quality good practically them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF combined it is lonesome measuring the let breathe that is getting next the MAF, suitably if the intake manifold is sucking in let breathe the freshen to fuel ratio will be unconditionally 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 can in the area of the hissing in imitation of the engine admin and bearing in mind you listen the engine stall or rev later there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.