Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to drive off a cliff. had a idle surge misery that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After trying 2-3 vary 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. help 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 later 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 every related parts (tps, maf, iac). 0-200 all grow old I agree to it complete the dealer for diagnostics.. on going problems are truly adjunct up. I m undecided to be next to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I did re-check them tho. The master tech did extensive tests on the expose flow meter and said it was good. subsequent to I unplug it and run the motor, the car runs brusque and at 850ish. I can unaccompanied guess that my other rebuilt ecu has an issue, or the tps needs to be re-adjusted, or someway my maf has died in the midst of every this. I don't think the tps has that much govern in the exchange of rpm though? I think it and no-one else adjusts it around 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you up to date on every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms up and is warmed up? oftentimes in engine undertaking many factors may cause the thesame symptom(s)