Engine missing a beat

[jtparr]

i have had this issue twice now in the last 3 months, the second time was on Sunday returning from Spa
Basically the engine looses power sharply and within a split second regains power...like an irregular heart beat or a hiccup....at first I wondered if it was dirty fuel as I had only a quarter of a tank and I had just exited the last service station going north on the M6 toll, which has a tight descending left hand curved ramp and perhaps debris was pushed within the rank then as I booted it it spluttered a couple of times....and then again two or three times over the next 5-10 mins....but the second time I was half full and was gently accelerating whilst joining the Motorway as we left the Chanel tunnel train ramp system in both cases the car had been running at around 4,000 revs for at least 2 hours and then sat idle for at least half an hour ...it did this about 3-4 times over the next 20 mins

Any thoughts people

I cracked off the lower fuel pipe from the fuel filter last night as it's easy to access and only clean fuel exited....and I couldn't see any obvious damage or loose connections on fuel/air pipes around the MFI/throttle stacks.....before I inspect anything else I would appreciate any advice....am wondering if it's related to a warm Engine, partly cooling and then re-started...?

Thanks

[KS]

Not sure if it helps but I had a remarkably similar problem on my '74 2.7 Carrera. In the end, it was traced by Autofarm to dirty/corroded contacts in one of the multi-plugs in the engine bay. Once cleaned up, the problem went away. Probably not relevant but may be worth a look...

[210bhp]

Your first description sounds electrical to me. A total sharp drop and then recovery. Your second description sounds like a fuel issue as they tend to be more spluttering.

Regards
Mike

[dogbower]

Collapsing fuel lines?
Took me ages to get to the bottom of similar issues, changed them and never happened since.

Stuart.

[jtparr]

Thanks guys...I will check the connectors and pipes (again) over the weekend

Mike...both occasions were similar..I think my description wasn't good enough....

all fuel lines are only 10 years old...but having said that I noticed a mildew type build up on the top surface of some of them last night....the engine bay is dusty but this was more a whiter deposit....is that a sign of the pipes deteriorating...once wiped down they looked fine...?

It's not exactly a big job to replace all the pipes in the engine bay...just don't fancy doing the long ones through the transmission tunnel...!

Thanks again

[sladey]

Check your earth straps - I had cut-out at speed years ago - intermittent. May be unlikely but simple to check

[Ian Comerford]

I had the same symptoms and the reason was the same as Keith describes. The main multi pin pug at the rear of the Cdi and fuse panel was very slightly loose. A bit of cleaning and tweaking the male pins made it a much snigger fit.

Ian

[jtparr]

Add earth strap and multi pin plug to pipes check session Saturday morning...!...

[Slope330]

especially as you ve just been into Europe ,Extra Ethylene,are your fuel pipes beginning to break down and get squishy?????

[dogbower]

.all fuel lines are only 10 years old...

I would say worth it anyway then, ones through tunnel are solid, just replace the flexinones
Stuart

[jtparr]

....bugger....all fuel lines are flexible....as I relocated the fuel pump to the front of the car I had to install bigger bore pipes for delivery...so stainless braided flexy pipes were used within the tunnel

Oh well...I will start with the easy ones and see how we go..