Twncam

[androb]

I have a s4 with a webber twincam engine in very good condition but it has developed a missfire at 90mph it has electronic ignition and I have done the normal things new plugs, rotor arm, cap,leads etc but it still persists ok through the gears up to red line but when in top a missfire at 85+ some one out there must have an idea where to look next

[wobblyweb]

androb
I had a similar problem with the Twin Cam in my 7 except that it misfired through the gears, I took it for a rolling road test and the first thing the guy said was throw the Electronic Ignition in the bin. It cured it although I was told later the type I had fitted was "rubbish" I guess that you have checked the rev limiter if fitted as well as the coil and condenser.
In about 18 years of everyday use with my Elan, one of the few times I have not made it back was because of condenser failure 350 miles from home.

Rae

[gjz30075]

I had a similar problem and a new coil did it for me. Sounds like your coil is breaking down.

Greg