1990 300zx Twin Turbo Wierd Hesitation

[300zxtwinz]

Okay so I bought a 1990 TT a few weeks ago, I got it for $1300... That says something lol.
Now that it runs it will only get up to around 4,500 rpm then it like bogs and won't go anyfurther like it's hitting a revlimiter at 4,500-5,000 RPM- only when -driving it in neutral it goes right up 7,250 rpm
-It's a 5 speed
-It boosts up to 8-9 psi before it starts cutting out so it's not in safe mode
-Also the ECU throws code 55 so that's no problem
-It has test pipes
-I believe Both turbos are bad the passanger side is knocking and blowing a lot of smoke (I'm getting new ones soon) the driver side just blows a lil smoke
-all new plugs correct gap
- I played with the TPS that didn't effect
-I might delete the prvr soon
Anyway after I got it i got the injectors cleaned and refurbished for the mean time it runs on all 6 cylinders now. When I pulled the plenum I did all the deletes
AIV, Egr solenoid, Carbon Canister. And under plenum coolant bypass. The EGR delete was done before I got the car.. Don't know if it was done right but it was done. So it starts right up and runs good besides all the noise and smoke from the turbos, but when I get on it it goes to say 8psi and like 5k rpms and kinda cuts like it's starving for fuel or something. It has a new fuel filter and new lines.
What do you think it is? I mean I know driving it with bad turbos is not good but I had to test it as this is what I found.

[nissanfreak12]

Test the fuel pressure, and check for codes in the ECU. Don't just rely on the CEL letting you know something is wrong.

[300zxtwinz]

What's a good fuel pressure? 40psi?

[nissanfreak12]

About, don't have exact number off top of my head. There is a FSM under everything you need to know abotu the Z32, that should tell you everything you need to know.

[300zxtwinz]

Hey man do you think that the VVTC could be the source if the problem? I know in my na z that right at 4500 like power band kicks in and the power really comes in there, it's like the tt I have just stops right before power band kicks in but I don't think my na z has the VVTC though.

[nissanfreak12]

All Z's 90-95 had vtc in TT form and NA form, the VTC normally kicks in at about 3k rpm. 96 was the only year not to have it. Normally if you have issues at higher rpm's when under load, its a fuel delivery issue, mainly above 4k rpm. If you have issues at about 2500 rpm's, normally the issue is MAF.

Have you checked the O2 sensors? Have you checked the ECU in mode 2?

[ThisIsSparTTa]

There's a huge section for all kinds of hesitations in the FSM. Also check out: http://www.twinturbo.net/nissan/300zx/FAQ/z32faq.aspx

[fabbio25]

My car was doing the same thing. Changed out the 20 year old boost intake hoses and replaced with z1 silicone hoses and problem solved.