Mk1 turbo misfire

[ukianj]

Looking for bright ideas. An intermittent misfire has developed in my last 3 drives. It's a 1991 Mk1, BEGi turbo 165bhp. I have changed the plugs and leads but that hasn't cured it. The misfire is intermittent at low revs but goes completely above about 4k.

Might it be related to fuelling?

[skinny]

more likely is coil pack i think...

[ukianj]

Mmm, I read that might be the cause elsewhere too. If it is the coil pack, will it just keep deteriorating? How easy/hard to replace?

[ukianj]

Mm, scratch that - clearly only a 5 minute job to replace.

ta

[MX-5 Lazza]

Might be. Something more basic such as coils are more likely though.

ETA: Doh! Beat me to it!

[ukianj]

Thanks both - will swap at the weekend.

[ukianj]

Mmm, no not the coil. After swapping took it for a quick run and all perfect. Put it away for the night and the following morning, fine for the first mile, then that misfire again. Limping back home there were occasional moments of clean running but probably 80% was in misfiring mode.

Injectors next? and if so, given i'd like to up the boost in the future, is it worth thinking about bigger injectors now? what are the ECU implications of installing bigger injectors? I'm guessing it's not a straight swap and it'll all just work...

[Noisy]

I'd say check the coolant temperature sensor is connected properly, it sits under the coil pack, sounds to me like a poor connection somewhere if moving things around under the bonnet when fitting the coil pack cured it on a temporary basis.