strange and alarming problem!

[B@fink]

Minding my own business today doing normal motorway cruise i accelerated to overtake (down a gear) before dropping back to cruise speed only to moments later have a engine/car vibration and a small loss of power (didn't slow the car, just didn't accelerate as it would normally) . Applying throttle and forcing a gearchange and it smoothed out, as did tipping down a cog manually. Panicing slightly, i limped to the next exit (no warning lights on neither engine managment or gear selection) with it sounding sick, stopped at the top of the slip road with it just keeping running (3/400 rpm) and chugged to a layby. Stopped the engine and aside from a warm car smell everything was perfect (oil, water, belts, hoses, nothing leaking) the ground was steaming under the cats but everything else was a-ok

Now very confused and not fancying a recovery trip i started the car again and..............normal. Perfectly normal. Like a new one normal. Pulled away with it absolutely fine, did a short experimental run all fine and have driven a further 350miles including many starts, 30mins in traffic, long motorway run and a lovely winding moors road all fine

What when ping, why did it go ping, how did it fix itself from being ping, and will it go ping again!?!? i'm open to ideas!

my only guess is i lost 2 cyls on the coil, it didn't report it because it couldn't be bothered, injected petrol without burning it straight into the cat which then produced the warm smell) and then magically fixed itself. HELP!

[IT]

Originally Posted by B@fink

Minding my own business today doing normal motorway cruise i accelerated to overtake (down a gear) before dropping back to cruise speed only to moments later have a engine/car vibration and a small loss of power (didn't slow the car, just didn't accelerate as it would normally) . Applying throttle and forcing a gearchange and it smoothed out, as did tipping down a cog manually. Panicing slightly, i limped to the next exit (no warning lights on neither engine managment or gear selection) with it sounding sick, stopped at the top of the slip road with it just keeping running (3/400 rpm) and chugged to a layby. Stopped the engine and aside from a warm car smell everything was perfect (oil, water, belts, hoses, nothing leaking) the ground was steaming under the cats but everything else was a-ok

Now very confused and not fancying a recovery trip i started the car again and..............normal. Perfectly normal. Like a new one normal. Pulled away with it absolutely fine, did a short experimental run all fine and have driven a further 350miles including many starts, 30mins in traffic, long motorway run and a lovely winding moors road all fine

What when ping, why did it go ping, how did it fix itself from being ping, and will it go ping again!?!? i'm open to ideas!

my only guess is i lost 2 cyls on the coil, it didn't report it because it couldn't be bothered, injected petrol without burning it straight into the cat which then produced the warm smell) and then magically fixed itself. HELP!

Sounds very coil pack related to me, seen that sort of behaviour before, but if it were Id defintely expect to see a cylinder or two reported in vag com, replace those coils and all should be well... ?

[B@fink]

only a single coil...... i'm a 2.8er. The coil was new 7 months ago! Its still fine today with another 200 miles on it. Never shown any indications of going wrong for the last 500 miles......its very wierd!

Vag com'd it before i set off, no engine fault reported, no gear box faults reported but it did report that the mid right parking sensor was poorly. Which is a miracle. I haven't got them!

[B@fink]

Sooo whilst taking the car for it's gearbag service we had a symptom repeat it lost 2 cyls whilst on the A1M at a steady 70, just sudden drop to 4 with a loss of power. I stopped it quickish (not the most fun in the world sat on the hardshoulder) and aside from the odd smell (fuel into cat?) I found no faults again no lights lit and everything full so I called it names, started it and it was fine, drove another 30 miles before getting stuck in traffic litterally 3 mins from destination and 4 cyls again. Figuring it could only be the coil getting warm and losing 1 of the 3 units feeding 2 cyls. I took my emergency spare with me when i went to pick the car up, did a roadside swap and it drove back absolutely perfectly (the gearbox obviously was super smooth) with what felt like more power and possibly more economy suggesting it might have been in declining coil health for a while (i usually only do little 6 mile hops to work, not long enough to get warm and loose the cyls) I took it back to supplier who have very kindly agreed to replace it (its heading on for a year old so I think they're being quite sporting really) but I have to wait for it to arrive so I might have got this little unreliability patch sorted. My fingers are crossed!