sc300pj

1JZGTE into 94 SC300 (non vvti soarer motor, auto w/ auto ecu)

When driving it seems as if the tach gauge "warms up", meaning over time 70 mph first read a few minutes into the drive is about 1k but about 20 some minutes in its at 70 mph is now up to about mid 2500 (normal?)...I got this off someone in a trade. As far as I know there is not tach adapter in place. When I get home and put the car into Park the idle goes from about 600 to 1000 rpms on the gauge and audibly sounds faster

When I go from P to R or P to D the car seems to 'sit back' and the idle lowers. The exhaust note also deepens. When I go back into P or N it audibly gets higher and the gauge reads higher.

When I stop at a light with foot on brake the car seems to get a weird vibration - as if the idle is too low? If I fluctuate the brake pressure while stopped then the idle seems to have a fluctuating response to where it will sound healthy to a bit unhealthy.

IT has never choked out and died while stopped, however recently in the am when I start it and go in reverse theres been times to where the idle almost dies right after I release the gas.

Not sure where to start on this one...dont want to start swapping out parts and chasing my *** on this.

Ali SC3

iTrader: (10)

all of that sounds normal except for the 1000 to 2500 at the same speed, probably have a bad tach I dont see how you are doing 70 at 1000rpm's but the stuff from 600-1000 sounds right. If you feel its dipping too low you just need to raise the idle speed a hair on the throttle body.

sc300pj

Had someone following behind and letting me know the actual speed. Pretty sure my cluster is about shot (temp gauge stays at first mark right above C, speedo wont read until about 10 minutes in but only gets up to 30mph at most no matter what, fuel gauge is just slightly reading lower than actual fuel level.

So the car sitting back when going in and out of gearing is normal? Maybe not descrbing that part right. P or N into any gear literally pulls at the car (like its engaging hard) no shuddering or loud noises with it. Just a feeling liek someone is literally pulling on vehicle when engaging

sc300pj

64 views and Im only getting one response?

So its entirely normal for the car to drop in RPM when switching into gear?

and normal for the car to have a feeling of a pulling back when shifting out of P or N into any other gear?

Ali SC3

iTrader: (10)

every automatic lexus/toyota I have owned drops in rpm as you put it into gear and will want to go forward. it sounds normal, you should have your foot on the brake. now what is your warmed up idle at in park, itif it is always high like 1000 that is a little high and the higher it is the more you feel the jerk when switching so that may be your issue. 8-900 in park is normal and 700 or so in drive is normal, but the idle numbers will be different for every motor. maybe someone raised the idle a little bit to cover another problem. Hard to tell without seeing it, but it does not sound unusual may just need some adjustment. also rough idle may indicate you could use new o2 sensors at some point and or plugs those help alot with idle quality.

If it feels like its driving fine and its just the tach is acting funny then you likely have a bad tach, they can go bad if you open them up and mess with the needle alot or just from age.

sc300pj

Thanks! Very helpful to know the tendencies!

As far as the idle itself, its not rough feeling like the motor will die. It seems to only be when I have the brake applied during idle - was thinking possibly a brake booster starting to move towards going bad and not holding vacuum correctly? If I pump the pedal while stopped I can feel the car react to it.

Studiogeek

iTrader: (6)

If you look at my recent thread about idle/voltage dropping when I shift into drive while stopped and it being normal in neutral or park, you will recognize some of the same behavior. Mine only actually stalled twice, but it happens every time. My brake seems to not affect it tho except for additional voltage drain. The drop in RPM is normal but my voltage drop is not.

Good luck!