Lexus 1S200 Revving To Redline Then Cutting...please Help

[ring_master]

hi all

im new to this forum and hope someone can help me i recently fitted a replacement engine into my 2001 lexus 1s200 due to headgasket failere. i fitted the new engine and now the car sometimes starts and is revving straight to redline by itself and sometimes starts and revs up and down when i try revving it just splutters and dies out and will not stay started.

any help would be much appreciated. thanks in advance

[steve2006]

Hello and welcome to the LOC.

As far as I know only a wide open throttle would cause the engine to rev up to its maximum so start with the throttle cable, make sure it isn't sticking or disconnect it at the throttle body and operate the throttle butterfly by hand directly from the engine compartment.

Varying revs could also be due to the throttle cable or possibly induction air leaks so check all your vacuum hoses.

I also assume the engine you have fittted is the same type as the old one or there could be incompatability with the engine and ECU.

It's a little quiet on the forums at the moment but I'm sure some IS owners will chip in with possible causes given time.