Ken2012

My experience with the SC400 last year is complicated by the technology, and terminoloy, i.e., the following recommendations:

The problems were not completely diagnosed since the scan tool wasn't communicating with the ECM; the EGR system was not operating and was completely replaced; the motor mounts were also collapsed.

I haven't replaced the ECM or the motor mounts yet; the ECM was quoted between $1,500-$3,000, so the motor mounts may be the next project for 2013.

Thanks for all the information in 2012; the results of the next maintenance year, 2013, will be reported to the Club Lexus Forum. Hope that helps.

Ken2012

I have two conflicting reports on the "shaking" problem in my SC400, i.e., misfiring/ backfiring, mostly between 40-50 mph, one report from a Lexus service shop and another from a transmission shop. Lexus replaced the EGR system, timing belt, distributor cap, etc., with some improvement, for $1.8K; however, this didn't completely fix the "shaking" problem and the misfiring/backfiring every 10 seconds or so, even at idle (which Lexus couldn't duplicate). The Lexus shop suggested this problem may also be from low octane gas use, a short term possibility due to someone I know. The plugs and wires were also previously replaced with NGK, no improvement. Lexus also said I need new motor mounts; the transmission shop said the motor mounts and transmission mounts are Okay and recommended a diagnostic check; the diagnostic check wasn't even possible by Lexus due to a slow processor in my SC. Sounds like I need an intervention or a new processor (up to $3K) for this Lexus. Any other ideas?