1994 ES300 rough idle (175K Miles)

[kperko]

My '94 ES300 starts immediately and idles nicely for the first 20 seconds or so then starts missing but not bad enough to quit.  I just replaced the plugs with Iridiums, new coil plugs, cleaned the EGR (which I replaced with a new one about 15K miles ago).  Cleaned the throttle body, put on new air intake hose, checked for vacuum leaks with carb cleaner, checked all coils and they are in good working order, replaced fuel pump and strainer and fuel filter, cleaned MAF sensor.

Won't read any codes on my OBD2.  Going nuts here trying to figure this one out.  HELP!!!

[gbhrps]

kperko,

Sounds like you have tackled just about everything except the IAC valve, the Idle Control Valve. It may be just dirty and needs to be cleaned, or its motor may be bad altogether and needs replacing.

Go to YouTube and check out "94 Camry IAC fix" videos, there are several, and possibly this will give you a solution. Good Luck!

Here's another step by step for a V6 RX300 that should be similar procedure, from a Lexus Forum:

     http://www.clublexus.com/forums/rx-1st-gen-1999-2003/358579-diy-iacv-clean-picture-write-up.html

[kperko]

The IAC was clean and in good working order but I did a thorough cleaning to rule it out.  I also replaced the EGV VSV but am still having the same idling issue as well as it runs like crap when under a load (accelerating or going uphill).  Going to try testing the EGR temperature sensor in the morning while the unit is cool.

[OU1]

Did this issue ever get solved?  I seem to be having a similar issue.  I have to crank the engine over 3 times to get it to start, and romp on the throttle to get it to stay running from a cold start.  Once the engine is warm it starts in 1 try.  However it is lacking a tremendous amount of horsepower almost as if it's in limp mode.  And on occasion coming to a complete stop it idles really rough.  And when in park is idling above a 1.