Hello everybody. That's my first post.

I have a Carisma GDI and I goes fine, but there is a problem that I can not resolve. Once the engine car is warm (after 10 minutes from start), the idle becomes irregular moving in between 500 and 800 rpm every second. However the car goes very well.

The idle oscilations never disapear when the engine is warm. But, (and that is the mysterious), when the car is ONLY idling for several minutes (from 6 to 10) then the idle becomes REGULAR again. If then I stop the engine and start again inmediately, the rough idle apears again.

The butterfly body had been dismounted and cleaned, and also verified that there is not any vacuum leak. The injectors could be coked with carbon but I'm not very sure because often I go near 6000 rpm in 2nd, 3rd and 4rd gear to clean the carbon.

There is another possibility that could be the "high pressure fuel pump" or the "fuel pressure regulator". I don't know.

Well, any ideas???

Bye

hey, i have a 1.6 carisma and i had fine idle until i put new spark plugs in it and set them as mitsubishi recommended. this gave me the same problem you have. I then ordered a set of mitsu plugs and it runs smooth.

I also had a problem where the car stuttered a lot in low revs or when trying to accelerate. Did an oil change with engine flush and new oil filter and with these plugs i've just about removed all signs of the stuttering and my idle is fine. I used semi-synthetic. also used redex before the oil change and before putting in the new spark plugs to try and clean the injectors.

your car has same problem as mine. It is the high pressure gas pump problem. My friend help me to check my car by using a special computer which directed connected to the ECU. The pressure is simply not enough.
The pump can't be repaired, as he said. the only way is to replace with a new one which cost over $1000 including labour cost.

I have't fixed it yet.