Vn won't rev over 2500 rpm

[Cappy]

Please help!!

I am doing up a vn but it has had this problem since I bought it. As soon as you put the foot down it starts to choke. When you rev it, it only goes up to about 2500 rpm before it backfires like a bastard. What do I do?
Thanks
Cappy

[FXST01]

Maybe a blockage in the exhaust system, possibly even the cat has had it.

[vamplestat]

go straight for the fuel pressure regulator mate, from my experiences, the Buick cant handle reeving past 2500 unless there is enough fuel pressure, so try replacing that

[Cappy]

Was thinking about the fuel pressure reg. It makes sense. Really doing my head in. Will let you know how I go.
Cheers

[vamplestat]

well it happened to me awhile back \when i was doing an engine change, park of the fuel pressure regulator got caught on something and slightly bent, the car started alright so i didnt think anything was wrong until i tried to move it or rev it up where all it would do is miss and backfire and strugle like a mofo... swaped the regualtor for another one i had and Bam no hassles for me then, so i would say thats your best bet mate.

[Cappy]

I was told by a guy how to check if it's the fpr. Clamp the return line off. It didn't stop the problem. Would it maybe the fuel pump not creating enough pressure?