Mitsubishi Carisma 1.6 misfire/hesitation at low revs

[timorridge]

Hi, I have a 2002 1.6 model which is recently suffering from a problem where it misifres for a couple of seconds mainly after applying throttle after a period of overrun. It is more noticable in top gear under 2000 rpm at 40-50 mph road speed. It picks up after and it is not a typical failed ignition type of stutter but more of a splutter which can be felt and impeded smooth progress. It also can appear (but not often) at lower speeds and lower gears again in the same rev range with low-mid throttle application. The car drives fine 99% of the time and is quite willing. I haven't notice any drop in fuel or oil consumption.

I have checked the air filter, intake box and flexi intake pipe for signs of leaks and read the codes of which none show. I guess it could be the spark plugs and leads but I thought i would check here for expert advice on what to try first.

I seem to be plagued with this type of the fault on older cars and never really found a solution. The only link between them is that I filled all them up at the same branded chain of supermarket petrol (not always same station).



Anything please ask because I will have missed something out.

[Mr2Mike]

Possibly you have a bad or misaligned throttle position sensor (I'm not familiar with the engine, but there may be an idle switch built into the sensor as well). When on the overrun the ECU will be cutting the fuel to the injectors above a certain RPM, with a fault on the TPS the ECU may not "see" you putting your foot down until the throttle is already opened a fair way.

[scarble]

Could be a vacuum leak, that intake pipe you checked probably has some more pipes coming off it somewhere, check them too.

[timorridge]

Thanks for all replies, I will check the vacuum pipes thoroughly and also do the plugs plus it needs an oil change and sees how it goes from there. I have had it 4 months and not sure of last times plugs were changed.

[scarble]

Be sure to note condition of and/or take photos of old plugs when you take them out. Consider replacing HT leads while you're there.

[DrDeAtH]

If its a GDI engine. Then a few tanks of super unleaded and an Italian tune will help. For some reason they coke up quite a bit especially if driven sedately.