Ok, it's a 93 wrx ra, changed 3 coil packs the other day, 1 had 2 cracks in it and 2 had very large cracks in them, only reason I checked was it had a slight miss when coming on boost, since changing them it seemed fine, but now when I change gear while I'm going for it, it cuts all power, or judders, it's fine all the way through the revs if I put my foot down in any gear, no miss at idle either, it's only when I change gear, only way I can explain it is it's as if I turn the ignition of while driving! When I let of and put my foot down again it's fine! Any ideas?

Thanks

James

 

Bump

 

Sounds like fuel cut to me. What boost are you running?

 

Standard boost, suffered over boost when I put a turbo back exhaust and it don't feel like that, changed exhaust bk straight after,

 

Bump

 

Bump

 

Check the bottom pipe on the boost control solenoid. there should be a brass pill/restrictor inside it. If there isnt then that will be your problem.