Car RPM problem

[syedshah201]

when i start my car and need to speed up as the car reach 50km/h the RPM suddenly goes to 50 and after that car back to normal and also my car is heating up as i think bc the heat radiator show above 90 but if it goes above 90 if you off the AC the heat bar goes down... any help will be appreciated.

My car is 307, (Model 2004) only One hundered thousand done.

[junaidh]

Hi Syed, it makes me feel two different issues. RPM jumping is may be cause of loose air flow meter socket or AFM is bad or even bigger gear is slipping and need gear oil change (which i doubt) or whole gear rebuild (worst case).

Second issue of overheating, it may be coz of radiator is choked, AC fan is not working as when u switch off AC it comes to normal. So get the AC fan check at first and see if your overheating get fixed. Once car is at normal temp see if RPM stop jumping. May be its co-related, but i really doubt as i am not sure. So get the root problem sorted first and spend less.

Good luck.

[syedshah201]

Thank you for your concern, i have recently changed the gear oil and filter but the problem remains still.

Secondly overheating, it only goes to 95 and stops there no matter how long you drive, please advise is it normal or it should not go above 90...

Thanks

[207_gti]

the temp should stay just below 90. the cause of this may be the waterpump, a racked radiator, or simply that the coolant or oil levels are too low.

as for the rpm issue, yes that could be that the MAF sensor is not working properly, a loose o2 sensor, faulty coil pack, or even timing...although with a fault coil pack or timing issue u should feel the car jerk when it drops the rpm like that