RPM shaking when temp is up!

[Samal]

Hello Guys

I have a 2007 Aveo5 saloon, Manual transmission 130 KM . about 11 Years,now I've been trying to nail down a pretty big issue that I've been having. Sometimes while driving, the car will suddenly lose power and/or stall out. It will drop RPM's, start bucking pretty violently, and slow down sometimes almost to a crawl. If I let off the gas it will completely stall, but if I keep on the pedal it will eventually recover only to stall out once in neutral or making a complete stop. Recently it seems to mostly happen once I let off the gas and cruise to a stop. When it's having issues it will drop down to very low RPMs at a stop, almost as low as 100, for a few seconds then either stall or jump back up to 800-1k.
the only time it stalls is at idle after the engine is throughly warm.


also when it is cold in idle mode if turn on A/C the engine will increase the RPM when it be normal warm won't increase the RPM if turn the A/C on, i have change the throttle body and change the sparks also change the fuel pump also check there is no leak of vacuum hoses, change the up stream o2 sensor when check it by the OBD there is not code and still same problem!! could you please advise for fix it? is this problem with the ECU unit? is there relationship between the ECU and increase the RPM? also i would like explain that when drive the car in cold everything is ok but when driving for 20 min and put the gear to N the RPM will come to 200 then back to 800 sometimes make the A/C off.
thanks you in advance


Would like to know if anyone else has had this problem and what fixed it; point me to something I missed while searching this forum, and/or offer ideas.

[Daox]

Is your throttle body a cable driven or electronically actuated throttle?

[Samal]

Hi Daox, thanks for your replay,

my throttle body is cable i have change the throttle body two time it's is the same, i would like to think other parts. i have read some in other site they said should be the o2 sensor or the fuel pump relay. i have replace up stream o2 sensor only is this symptoms of the down stream o2 sensor?