malfunction indicator light and spark plugs

[fish-face]

Help! My dad used to service my car, but he recently died, so I am trying to remember what he taught me. I changed the spark plugs on my Daihatsu YRV, which had 3 prongy-things, but the ones that I was assured by the motoring shop were the correct ones, only had 2 prongy-things. After having driven about 30 miles, the malfunction indicator light came on (orange, engine logo) .

I rang Daihatsu who were surprised that 2 prong-thing sparks would have caused this to happen, and suggested putting the old ones back in, which I have done. I started the engine after putting the old sparks back in, but the MIL was still on

Is it possible that changing the spark plugs did this? I replaced the air filter at the same time.
Does it take a while for the light to go off, after all, it took a while for it to come on?
Have I knackered the engine?
Is there some other reason for the light coming on?

I'd be grateful for any help, especially since my oracle is no longer at the end of the phone to help me.
Cheers
FF

 

[Hitachimad]

Have you gapped the plugs correctly??
Have you replaced the HT leads in the correct order?

 

[fish-face]

Thanks for replying so soon!

I replaced each spark plug one-at-a-time, so that I wouldn't get the HTs mixed up. The HTs have a cover that screws into place, rather than the others I've seen that "pop" on.

As for the gaps, the chap at the motoring shop I spoke to when I rang about the fact that there were only two prongs on the new plugs (Bosch) said that the gaps were pre-set - on the pack they say 0.9mm. Two choices of plug in the hand book did not include Bosch (ones I ended up with), but specified 1.0mm-1.1mm or 0.9mm - 1.0mm for the two suggested plugs. However, I have since put the old plugs back in and drove to the end of the road and back (half a mile) and the MIL has stayed on. Hope that helps?
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