I got in the car yesterday lunchtime and over about a 15 min drive through town (approx 3 miles), the engine started idling badly, revs dropping/rising by 200 revs every few seconds. When pulling away it would stutter a bit until revs got over 2k. I decided to leave the car overnight with battery isolated hoping it was an electrical gremlin.

Got in the car this morning, and was getting the same issue, except it got worse over 1.5 miles or so through traffic to the point where I turned round and went home. Engine was stuttering/underpowered under light acceleration up to 3k+ rpm and was making a slight farty sound and intermittent popping sound (in my head this was unburnt fuel hitting the exhaust every now and then but I have no proof).

I've checked the MAFs are plugged in securely (had that before causing an idle problem before) but that's it so far. Next I was going to look at the coil packs (although I changed these about 2 years ago) - I'm hoping somehow a connection has come loose. I was going to disconnect one plug at a time and see which disconnection didn't make the idle even worse...sound sensible?

Any other suggestions?

And of course this all did just have to happen a few days before Dads Day Out where I'm supposed to be driving both days

have posted in CS....might put in Fchat as well if I can remember my credentials....

Not sure I want to drive it down to Autofficina in case it was doing damage. Which would only leave getting it trailered. I've already had Locktons free breakdown out a couple of times for flat battery etc, wonder when they'll start telling me to get lost

just a thought but if you get your car looked at by Autofficina, why not call them for advice?

You could disconnect both MAFs and see if this improves things, the car will default to a table of values rather than relying on the reading from the sensors.

Okay, just had a fiddle and a play. I checked all leads were securely plugged into the coil packs, checked the plus were secure too. then took the MAFs off and had a look. They seemed fine (as best as I could tell), I put them back on, checked their plugs were secure and clean. Checked the idle control valves, nothing obvious seemed untoward there. So, I started the engine and initially all was fine. Then, as it started warming up to temp, it started doing it's little hunting thing, revs rising and dropping by 200rpm of so every 5s or so. I disconnected the MAFs and the only effect was that it idled a bit lower but there was still the little amount of hunting, so no different to before really. Then tried to pull away to do a mini test drive to sainsburys 500 yds away, but after only 30 yds I could feel it was doing what it was before, being hesitant, losing power and stuttering a bit while sounding like it wasn't firing properly on all cylinders, so reversed back and switched off.

From my limited knowledge, since it only seems to appear when the car is warming/warmed up, I'm thinking it's like a spurious signal from say a lamda sensor maybe that's causing something weird on one bank that I'm mistaking for a misfire. Or maybe a HT lead that once it starts getting hot is not working properly. Less inclined inclined to thinks it's a spark plug(s) as they were all replaced last year.

Anyway, whatever it is, it means I can't drive at the supercar event tomorrow so I'm v disappointed But thanks to Mark (Fozzy008 I think) for the ride in his Diablo there today. Sounded fab from inside and my first ride in a Lambo

I once had this on one of my 355s. It turned out to be an ht lead that was arking out on the engine. Replaced lead and plugs. Good as new.

hi mario.

have you checked that the joint of where the 2 ducts that come from the airboxes and then meet is still tightly coneected with the jubilee clip? if that joint comes loose the car sounds like, and goes like, a pile of crap.

I'm thinking that if it is something simple like one of these things, I'm going to try and just get a regular local mechanic/breakdown person to come take a look. They could confirm/sort it (no black magic on these cars) and it would save me the grief of having to get it trailered to Autofficina/Paul Coster. Unless there are any amateur mechanics in SW London willing to pop over with relevant tools this afternoon in return for some beers?!

Street Triple was stolen last week I'm not having very much good luck at the moment

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