miss fire

[DCerebrate]

Hi, Cerb happily went to Edinburgh via A70 (bottoming out on C roads near Sorn)! Coped with traffic fine. Great along M8 on the way back, satisfied growling while lapping up petrol at 70. Reaching Ayr, a misfire - up to 3000rpm. Seems to clear its throat above this. Had car to garage today for check with Ollie's software - no fault codes historical or new, and they said was running fine. Plus they checked coil. Any clues? Thanks

[Billiam]

Hi DC, sorry to hear about your niggles.. the HT leads are a common weakness so i would suggest that next port of call ? One other quick try, after long motorway - did you stretch the engines legs at all ?? Sometimes a blast up through the revs full throttle can help clear her throat so to speak !

Sorry i cant comment any further, hopefully someone more in the know will come by with some other possible causes but i wish you good luck with a quick and easy fix !!

[nawarne]

Billiam said:

Hi DC, sorry to hear about your niggles.. the HT leads are a common weakness so i would suggest that next port of call ? One other quick try, after long motorway - did you stretch the engines legs at all ?? Sometimes a blast up through the revs full throttle can help clear her throat so to speak !

Sorry i cant comment any further, hopefully someone more in the know will come by with some other possible causes but i wish you good luck with a quick and easy fix !!

I'd agree - HT leads and then coil pack.

Double check plug recesses are bone dry and HT lead cover is well sealed.

Nick

[gacksen]

lambdas have been checked ? fuel system has been checked that filter pump and pressure is ok ?

[DCerebrate]

Thanks guys, garage has been busy, still awaiting investigation of misfire. Fuel pump / injection sounded a possibility, but would it not then get worse above 3000rpm instead of better? Will update when / if resolved!

[Basil Brush]

Is 3k rpm where the lambdas stop being used in closed loop?

[DCerebrate]

Don't know, but picked up car today, running smooth for now. All that was done was to reset adaptives and minor adjustment to TB spindles (I think). So one happy owner on the way home. Planning 250 miles over w/end, incl Central Scotland TVR meet on Sunday. Thanks for all advice.