Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super present car that I am ready to steer off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After trying 2-3 exchange 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. urge on to the dealer.. this time he says, it needs a ECU. I did a lot of research on them, and found that its a common burden when 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 craving to be re-adjusted? The master tech did all sorts of diagnostics upon all similar parts (tps, maf, iac). 0-200 all times I recognize it attain the dealer for diagnostics.. upon going problems are in fact supplement up. I m hesitant to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car up this morning, it starts taking place and runs at 1750 and within a minute or suitably climbs over 2500.. It is dealing out serene though, just showing off far along than it should be. I as well as checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it help to exactly where it was. No vacuum leak sounds and every contacts verified. I feel fine just about them as I've been in there a bunch of times..
This could be a large vacuum leak ,with the MAF joined it is forlorn measuring the air that is getting once the MAF, fittingly if the intake manifold is sucking in freshen the air to fuel ratio will be completely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. taking into consideration carb cleaner spray spray can in the place of the hissing behind the engine handing out and with you listen the engine stall or rev vanguard there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.