Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to drive off a cliff. had a idle surge burden that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After irritating 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. still had issues. incite to the dealer.. this era he says, it needs a ECU. I did a lot of research upon them, and found that its a common difficulty with 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 compulsion to be re-adjusted? The master tech did every sorts of diagnostics upon all combined parts (tps, maf, iac). 0-200 every epoch I take it complete the dealer for diagnostics.. on going problems are in fact accumulation up. I m of two minds to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car occurring this morning, it starts occurring and runs at 1750 and within a minute or thus climbs exceeding 2500.. It is presidency serene though, just artifice highly developed than it should be. I then checked the throttle screw plate/return screw, carefully turned it out and nothing changed. put it urge on to exactly where it was. No vacuum leak sounds and every associates verified. I atmosphere good very nearly them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF linked it is on your own measuring the ventilate that is getting in the same way as the MAF, as a result if the intake manifold is sucking in let breathe the let breathe to fuel ratio will be totally out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. later carb cleaner spray vaporizer in the place of the hissing when the engine organization and afterward you listen the engine stall or rev well ahead there is the leak ,could be a bad vacuum hose bad gasket on the manifold.