After I clean the throttle body and MAF on my 92 LS400, the RPM start a little higher then 1000 and idle roughly. After 30 second, RPM start decrease (I can feel the car is shaking) then engine die. start it again and it die within 10 secounds. I wait for two hours and try again same thing happen (RPM start a little higher then 1000 and idle roughly. After 30 second, RPM start decrease then engine die.)
I unplug the MAF sensor nothing change.
I use CRC mass air flow sensor cleaner and CRC Throttle body & air-intake cleaner

Any one know why?

 

you must rave to 3000rpm to clear all those you spray in youre throttel body .. within 3mins with full aircon blasting..& rpm a bit higher, those chemical you spray into causing em.. engine shakes combustion chamber clogged after those carbon deposits goes down to combustion chamber.

thats what i do when i clean up the throttel body & intake cleaner... but mass airflow cleaner? hmm.. yet again try diagnosis if the problem persist to come back.