Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super spread around 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 irritating 2-3 substitute 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. put up to to the dealer.. this mature he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem past this car.. bought a used one.. more trouble. had the indigenous 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 on all aligned parts (tps, maf, iac). 0-200 every epoch I resign yourself to it reach the dealer for diagnostics.. on going problems are in fact additive up. I m hesitant to be next to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I'm 1500 too high.. or more. It's boggling to me how this problem has morphed into various idle problems and has everyone perplexed.. or correspondingly it seems. I've been dealing similar to this in the past July.. makes me appreciate my 240z 10 get older more.My dad owns an sc400 and its been essentially fine to him.. I'm having a hard time not being caustic gone this purchase. I attain character with its a good car though. Motor sounds lovely and is super serene in the manner of handing out right.
subsequently I start the car, the engine surges stirring amongst 1200 and 2000 rpm back up and forth. I changed the IAC and the TPS once no change in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to familiarize the idle speed screw to belittle the rpm and it would preserve for a while. Now, the engine is at all times surging to the dwindling where I cannot drive it for buzzer of damage to the drive train. Any experienced solution?