over the last few days my 93 wrx has run very rough when cold ie hesitation pops bangs from exhaust ect when the car is warm this hesitation goes but it runs rough from what i think is intermittent coil pack failure only on full boost (1.1 bar) 4k + rpm i will get those changed yesterday after a run i noticed black smoke on idle and a little today on startup black then blue for a few seconds then to the usual vapour im not sure whats causing this could be turbo related ? air leak ? cars not using any oil has recently had NGK 7s fitted gapped to 0.7 any ideas if the turbo needs replacing which should i go for looking for 350 - 390 hp if i dont go 16g the car has
cdb
3 port
large KN cone filter
FMIC
HKS SSQV
stage 1 rcm fuel pump
rcm 550 s
omega pistons
acl bearings
crankcase breathers
SS headers
SS uppipe
SS downpipe
SS decat 3 inch rcm exhaust with prodrive backbox
performance clutch
ESL MAF less ecu
AP brakes all round + goodridge hoses
19 inch alloys
spax suspension
gearbox has been changed at some point and a few years back the engine was rebuilt
so if turbo needs replacing do i go td05 16g and have the map tweaked from 1.1 - 1.5 bar ish or 18 - 20 G i go easy on the gearbox
thanks for your help guys

how much is the car worth how it is ? might just get rid tbh

 

You don't mention a remap in your list of mods? Is it mapped for the mods and who by?

Black smoke sounds like massive over-fuelling..... I assume you aren't blipping the throttle before turning the key to start it?

 

car was ESL MAFless mapped a few years back at this spec
and yes no blip
and another thing a few days back it took about 8 turns of the key for the fuel pump to prime has primed fine since then
/update
if i put my foot down past 3.5 k rpm tries to boost but loud bangs from exhaust more hesitation

 

anybody point me in the right direction

 

could be numerous things - over boost and hitting boost cut, pipe off - intercooler or vaccum pipe, injector oring leaking, injector issue, mechanical issue etc..

Simon