Hi all,

my car is a punto 1.2 8v 2001 has done +200 000km.

As described in the title I'm experiencing loss of power on 5th gear, the car seems to stuck at 3.5K rpm barely 4k on flat road. on other gears it's doing well and cruising endlessly. I've also noticed an increase in fuel consumption and poor mpg (8.5L for 100km extra urban) the dashboard shows an average of 20km/L as max.

I have no idea about from where to start the diagnosis since the car showing no warning lights on te dashboard or recording in fault codes in the ECU.

I've started with reading the output from the O2 sensors but my knowlegde is very short about getting an insight from that. Herein a screenshot from the output:
I couldn't upload the screenshot i don know why

i'll try to edit and post the results as soon as i can

Could you please advise me on where to start digging?
Your ideas will be really appreciated

If any doubt, pull off the O2 sensor's connector and try the car. If your problem is gone, then you have to change the O2 sensor(s). It's free to try.

kido resuri said:

If any doubt, pull off the O2 sensor's connector and try the car. If your problem is gone, then you have to change the O2 sensor(s). It's free to try.

Click to expand...

I'll try and post
Thanks kido

I disconnected the O2 sensors, there was no difference. 3rd gear up to 100km/h but 4th and 5th gear barely reach 120km/h.

Is there a relationship between the amount/level of fuel in the tank and the performance of the engine?