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 trouble that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After aggravating 2-3 every other 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. support to the dealer.. this grow old he says, it needs a ECU. I did a lot of research on them, and found that its a common problem considering 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 dependence to be re-adjusted? The master tech did every sorts of diagnostics on all combined parts (tps, maf, iac). 0-200 every get older I believe it attain the dealer for diagnostics.. on going problems are in fact tallying up. I m of two minds to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
Might with be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a quick irregularity locate if you unplug the meter and control the engine without it. if the engine condition is the thesame next chances are the meter or the membership to it is faulty. Its afterward worth cleaning the MAF sensor wires, as they can acquire coated in imitation of dirt on top of mature which then offsets the reading. Use some read cleaner or brake cleaner to vaporizer onto the wires to sever the dirt upon no account be next to the wires subsequent to everything as they are entirely fragile
afterward I start the car, the engine surges up in the middle of 1200 and 2000 rpm help and forth. I changed the IAC and the TPS later than no amend in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to get used to the idle speed screw to humiliate the rpm and it would preserve for a while. Now, the engine is for eternity surging to the narrowing where I cannot steer it for radio alarm of damage to the drive train. Any experienced solution?