Rb20 problems, need abit of help

[Cracka Matt]

to start I have an 89 240 coupe with a rb20det, 5 speed transmission. Im having a weird issue that I cant quite track down the solution to. now then, let me describe the issues:

Strong gas smell with black smoke. lose of powerpoor gas mileage(horrible really)studders at times, wants to shut off when releasing the throttle. and once its shut off its abit difficult to restart it.

now on to the things i have checked.fuel pump running goodalternator, battery charging/holding chargenew fuel filter(needed to change anyway, unrelated anyways)new spark plugs gapped to .32checked for vacuum leaksmaf tested out to be workingno unplugged wires that i can find.turbo in good working order

so yeah may be more things Ive checked but I cant remember all of em. and my mods are as follows:

RB20DET,ARP Head Studs,GReddy 1.2mm Head Gasket,GReddy Timing belt,Fidanza adjustable cam gears,Hybrid FMIC and piping,Turbo XS BOV,HKS pod filter,3" exhaust with Fujitsubo NGK axle back, Koyo radiator w/ dual 12" fans,GReddy EManage,GReddy Profec E-01,HKS Hypermax D coilovers, front camber plates,Cusco front strut bar,Cusco front tension rods.

so if anyone can think of anything i may be missing id really appricate it. Im kinda busy at work(Army) most of the time and dont get alot of time to trouble shoot the 240.

[Cracka Matt]

oh and i did replace the coolant temp sensor as well, and tried adjusting the tps but no change

[onepuff]

fpr??

[Carl H]

checked timing?boost leak?BOV?

[ripracer]

If it doesn't already have one a Fuel Pressure Regulator like stated above, or the BOV.

[Cracka Matt]

thanks for the replys guys.

bov is not sticking open or anything like that. working just the way it did before this issue started. timing is dead on, again right where it was before this happened. cant find a boost leak if there is one, and it builds and holds boost fine, factoring in that it studders and all that...as for FPR, yeah it may be sticking open, im trying to get ahold of a pressure gauge so I can check that.