Here is my name, Fabien

My friend bought a 323F 2001 with 58 000 km, it's the 1.6 DOHC engine with 98 HP ( 72 KW ). We live in France

We got a problem to make the car running great.

For now, the car start and idle correctly cold and hot... The problem is when we want to throttle...

The car got VERY VERY low power... it bog a lot... I got some video to show you what's wrong with this car :


When we go for a ride it's a lot WORST... It's not running good at all..

Sometimes the check engine light come and we got : P0171 too lean code... But 90% of the time, no check engine light. BUT even if there is not check engine, the car ALWAYS run like this... Really bad.

Spark plugs are reaaaallyyyyy white...

For now we changed :

  • Timing belt
  • Camshaft sensor
  • Crankshaft sensor
  • Fuel pump
  • Spark plugs
  • Air filter

And we checked the intake tube if there is no crack.. of course no crack

We cleaned fuel injectors..

What can we do to make the car run better ?

We made engine compression test, we got 12 bars on every cylinder so ~175 PSI...

I know this engine is almost the same as mazda protege.. So this is why we try something here ! We know how to use wrench so if you have something please tell us.

Thank's !

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Jan 21, 2020 at 13:28

2 Answers 2


My suggestion is to look at the throttle body, specifically at the throttle position sensor (TPS). You need to see if it has the right output. You can either do this by looking directly at the computer (through an OBDII device), or by measuring the output at the TPS itself using a multimeter. In either case you'd be looking to ensure there is a clean sweep throughout the throttle range. In the computer it shows up as the throttle %. At the TPS itself, you'd be looking (once you figured out which pins to test) to ensure the resistance goes up/down cleanly with movement of the throttle.

When the TPS goes bad (or possibly has dead spots in it), the computer doesn't know to increase fuel delivery through the injectors, so a large mass of air is let into the engine without the fuel to compensate. It will idle just fine, but when the air hits it as the throttle opens up, the engine will run very lean producing the code you're talking about. I can't tell you for sure this is the issue, however, it sure sounds like the issue. Ensure you test the TPS prior to getting it switched out. If you do, you'd need to do a throttle position relearn on it (I don't have the information in front of me to tell you how to do that). The computer needs to understand what the TPS is telling it so it can run correctly, so thus the relearn is needed.

  • Hi, i tried to get information about OBDII port. i saw the TPS %. It seems to work correctly. I tried to throttle foot on the floor and i got 98%, when idling i got 0% so I think my TPS works fine right ?
    – LegeekX3
    Commented Jan 22, 2020 at 12:53
  • And here is some more videos : youtube.com/watch?v=95wUlbk6Wb8 youtube.com/watch?v=qWOhAl8iIFo
    – LegeekX3
    Commented Jan 22, 2020 at 12:55
  • Ok finally got it, it was the MAF ( airflow sensor ). Now it's running great
    – LegeekX3
    Commented Sep 2, 2021 at 14:49

I would suggest removing the front oxygen sensor the one closest to the manifold. Leave the sensor out and see if it runs better...it will be louder because of the sensor being out but if it rev's up like it should then you have a plugged exhaust... Most likely the catalytic converter is bad. I think that's the whole problem...

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