4g91 problems.HELP!

[dummy7]

my car's rpm will drop from normal 900 to 500-600 when driving in the hot weather, especially noon time. and d car performs damn sucks at that time! bt during early in the morning o at nite, d car is ok, i mean d rpm idles stable all d time. anyone driving 4g91 facing d same problem? another thing, i dunno other 4g91 engines, but my engine, when i'm cruising, no matter in highway o street, d rpm will suddenly drop a bit, for like 2 sec, den goes bec to normal. is tat normal 4 a 4g91? pls pls......need help here!!

 

[lighting4G]

maybe ur isc /stepper motor at your throttle body rosak edi.... check oso ur fuel regulator...
same thing happened to my 4g91 lasttime.. change both now every thing ok edi.
good luck to you.