Hi there, im new here . I own a fiat bravo 1999 80 1.2 SX, and have a problem with jumpy revs at idle once i have been on a long run when the engine is warm. It is fine most of the time idleing at 800rpm but sometimes the revs jump between 800 and down to 500rpm, lights dim and sometimes the engine stalls because the revs drop too low. I have changed the spark plugs and cleaned the air inlet valve but the problem still exists , anyone who can help me? Ive heard it could be the lambda sensor??

Cheers

join the club

throttle position sensor is my next point of attack.

hey thanks for the speedy reply. I cleaned this valve a week ago after finding it on the forum, gear change is now smoother, but the problem still exists. It only does it after a long run when the temp sensor is about half way on the meter, any other ideas? cheers

i'm taling about the throttle position sensor, not the butterfly valve.

failing that, try replacing the crankshaft position sensor.

ahhh right. is it possible to strip it down and repair it? or will i need to get a replacement from the scrap yard?

cheers

a TPS is basically a small arm that moves along a track to change the resistance of the TPS. you cant repair it, but you can try cleaning the track with contact cleaner, but be careful, if you open it up you tend to lose bits.