R32 Gtst, Running Lean? Popping Sounds? Airleak?

[BOOSTA]

Hey guys,

I've searched through various posts to try and find a solution but im just not sure if any of the other posts have the same problem.

I currently have a

1989 R32 gtst

Rb20det

3" hiflo cat and bee-r exhaust system (standard dump pipe)

HKS pod filter

Standard Bov

HKS spark plugs (havent changed since buying car as in good condition)

Standard Intercooler

Standard BOOST 9psi (spikes 10-11)

Since buying the car 5mnths ago it has been fine but for the last 2 weeks the car has been excessively backfiring,popping all over the place ( during gear changes, only when i come off throttle).

Its not missing during any part of the rev range but when i start the car its very lumpy, like barely wants to start running but then speeds up and idles fine.

It seems to be starting to lack power under full throttle and im abit worried about if it might be leaning out but i dont know how to check to see if it is.

Could it be a airleak at the exhaust manifold or standard dump pipe?

The heat shield over the standard dump pipe is getting pretty rusted so im wondering if removing it will cause any issues with heat?

Someone drove beside me the other day after following me up a hill and asked if my car was leaning out? They did say i wasnt blowing any black smoke under full throttle etc and getting pops/backfires everytime i change gears or just release the throttle?

Im only a 2/3yr apprentice mechanic for kmart tyre and auto and I dont have the amount of $$ to get it on a dyno so was wondering if theres any way i can check stuff to see if certain things are working ok? my clutch is starting to slip alil so i have to save for that aswell so if anyone can help with any idea's or ways to help try and sort out whats going on would be greatly appreciated.

Many Thanks

Pete (BOOSTA)

[r3225t]

check your afm and crank angle sensor, (and all other sensors) try swap it over from a mates car or something, also if it is leaning out & detonating it will stuff the plugs so u will need a new set