Daytona 600 idling issue

Hi all

I've recently brought an 04 Daytona 600 which was running fine when I first brought it but it seems to be having a problem with idling. I've done a service on it and changed the spark plugs to iridium plugs etc and now once its started it will idle at around 1200rpm and then drop to 400 - 500 rpm maybe lower (almost cutting out completely) then rising back to 1200rpm and it keeps doing this over and over.

Also when I'm pulling away from traffic lights or roundabouts etc it doesn't seem to have enough power so I have to over rev it and keep the clutch in slightly to have a chance of pulling away quick enough.

Any idea as my brains about to fry figgering out what's wrong. Its got an aftermarket can on it and also its been remapped by the previous owner.

Thanks

 

I took out the iridium plugs and put the old ones back in and now it runs fine, I tried using the tune ECU program but it kept crashing on my computer so I gave up on it.

Thanks guys

 

It's still bogging out when I'm pulling away from stationery so not sure if that's got anything to do with the mapping or not

 

Ive remapped it using 20034.hex which doesnt seem to have solved the problem, it already had 20035.hex map already on there. which map would you recommend putting on there?

i'm trying to avoid having to take it to a garage to fix if i can help it.

 

Thanks screwball, I think I've sorted it now!