Hello all,

I was driving my mom's '99 RX300 the other day and noticed a couple of things:

1. When at a complete stop with a foot on the brake, sometimes the rpm
needle will rev up to 2 and then return to the normal position and then
just keeps fluctuating back and forth. What could be wrong?

2. The car shakes when braking - I'm not sure when the brakes were last
serviced. Any ideas?

Appreciate the help in advance!

Ben
.

 

Ben,

1. Is likely an IACV issue, see here how to rectify it https://www.clublexus.com/forums/sho...d.php?t=358579

2. Those are likely warped rotors. You can either get them replaced or machined/turned (a.k.a. smoothed down).

Ron

 

Thank you very much for such a quick response Lexmex!!!

 

the braking issue probably is your rotors, i have the same issue in mine and i believ eit was due to getting a tire rotation at jiffy lube and them tightening the lugs on too tight and warping the rotors

 

A bit of variation is normal as the engine rpm is regulated based on load. When you mention "2" I assume it is not 2000 and I doubt you can register 2 or 20 so it would be 200 rpm.

A/C compressor kicking in and out.
Electrical load changing, such as brakes lights turning on/off.

Once you discount for these, IACV would be the next suspect and then vacuum. Also have the OBDII dumped to see if there is a pending fault that might help you diagnose it.

Now a days, due to emission concerns, no one [including dealer] messes with idle.


Salim

 

Is the engine revving up to 2000rpm or just the tach needle?