my car fiat bravo 1.2 16v 1999 is revving itself when idling - when cold it oscilates btwn 1500rpm & 2000rpm then soon after it shoots to 3000rpm and never falls back.
there is no engine light. changed the throttle body twice still no effect - traced for any leaks from servo to breathers and all is fine. when i check all spark plugs they are dry sooty black, also the lamda sensor is also sooty. the car used to misfire but change spark plugs before the problem and never misfired.

this problem happened after filling a full tank of petrol and pouring stp injector cleaner ( that was to solve the misfiring - but since changed plugs and leads)
I aslo put oil treatment as the car will make blue smoke after being parked for days implying the valve seals had hardened - the treatment was stop leak that acts as a valve seal softener. since then there has been no blue smoke but normal condensation colour. however this colour tend to be a very light thin grey to white which is consistent with the high rev problem i have. i seem to lose water slightly but the is no leaks and no mixing with oil. the fuel pump starts normal with key.

i have run out of ideas please help advise

When will people learn to read properly

Wrong forum! Try the correct forum for your Bravo. You'll fare better there for an answer to your problem.

if its also misfiring under load do a compression test to see if the head gasket has blown, especially between 2 cylinders (you'd see very low compression on 2 side by side cylinders). its common on the 1.2.


if its only an idle problem try using washers to space the throttle position sensor from the throttlebody. that often cures the 1.2's idle problem.

BRAV-OH!! said:

When will people learn to read properly

Wrong forum! Try the correct forum for your Bravo. You'll fare better there for an answer to your problem.

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did you have a bad day or are you grumpy all the time

jug said:

did you have a bad day or are you grumpy all the time

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Neither.

It makes the forum so much easier to use if you post in the correct section. You'll get an answer quicker that way.

BRAV-OH!! said:

When will people learn to read properly

Wrong forum! Try the correct forum for your Bravo. You'll fare better there for an answer to your problem.

Click to expand...

Which is the correct forum then as i am new to this.

jug said:

if its also misfiring under load do a compression test to see if the head gasket has blown, especially between 2 cylinders (you'd see very low compression on 2 side by side cylinders). its common on the 1.2.


if its only an idle problem try using washers to space the throttle position sensor from the throttlebody. that often cures the 1.2's idle problem.

Click to expand...

Thanks for your attention - really helpful -
I feel the problem stems from the throttle position sensor ( TPS and IAV are all in one - throttle control unit).

I did disconnect the unit off the throttle body but still connected to the ecu. then started the car and used my hand to manually let air in the throttle. surprise the car would idle no problem.

but by doing that I cant pin point the culprit to the tps unit as the ecu could be giving out the wrong signals to the throttle control unit or vise versa. or the ecu is getting the wrong reading from other sensors that support the throttle control unit.

cause lambda sensor calculates the ratios then sends signals to ecu then ecu talks to the offending culprits like wise. eg more fuel then the throttle control unit will put in more air. hence the constant idle at 3000rpm could be a fuelling problem as the lambda & throttle unit try to compansate. if this is the case how do i diagnose the injectors or the petrol pump to the relays. then again i could be wrong.

d06xft said:

Which is the correct forum then as i am new to this.

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The one on the forum page that says............

Bravo / Brava
1995 - 2001
FIAT Bravo / FIAT Brava discussion and information.

You'll have more chance in there as it's for your specific car. Someone in there might have had the exact same problem and have a solution for you. In this forum it's the new Bravo only. Less likely to be able to help you in here as we don't have the same cars.