2009 1.6TI idle issues

[Mattw]

Evening all!

Bit of advice required before I go diving into diagnosis tomorrow. My 1.6ti started this morning (cold) with a rough idle, needle on dash fluctuating. Got to work, came off the throttle to swing around and the engine cut out. Left it till tonight, started again and engine idle fluctuates between 800-500RPM. Once warm, idle would sometimes sit at about 1000rpm, then fluctuate again. Accelerated into workshop, struggles to pick up initially, but ok after, then after coming off throttle vehicle idle goes all Pete tong again very nearly cutting out, recovering and repeats.

I know coil pack and leads are a weak point - for those in the know, is this a symptom of failure of these?

Particularly fustrating having only just fitted some pilot sport 4s to have a play with!!

Thanks in advance!

Matt

[ChrisM41]

It could be the VCT system, which normally means it sounds like a diesel from a cold start, or it could be an air leak.

[Mattw]

It doesn't sound like a diesel, just fluctuating idle. At least I'm hoping it's not the VCT!

Relatively confident it's not an air leak, had a good look over last night before giving up and taking a corsa home. Had a can of brake cleaner over all the air pipes I could see, engine didn't pick up on it at all. May be smoke testing it tonight.

[ChrisM41]

Try resetting the adaptations, just disconnect the battery for a while. Let it idle on restart and take it for a run to relearn, it might settle down.

[Mattw]

Had a play last night after work, smoke tested all OK. Noticed the MAF sensor looking a little dirty, so pulled that out and cleaned all the gunk off it. Ran it up and touch wood so far seems fine! Will be tested from cold this evening.

Depending what it's like the evening may try the hard reset route, is there a specific drive cycle that's known to be best for them?