As soon as I hit 2300rpm in my Evo VII the fuel pump relay on the firewall starts rapidly switching on/off and continues to do so till about 3500rpm
Always happens at exactly 2300rpm, and stops as soon as the revs climb

What would cause this? My understand is the relay on the firewall is fuel pressure activated?

Is it more likely to be a faulty relay? Or a fuel pressure issue, maybe a dying fuel pump or faulty regulator?

 

Start with the relays. Should be two speed fuel pump relays, one for cruise, one for WOT. ECU may be switching fuel maps at that RPM and the relay is failing.

 

Is the relay triggered by the AFM?
There is no check engine light, but I thought I'd just check engine codes to see what I got
And I've got

P0110 Intake air temperature circuit malfunction
P0100 Volume airflow circuit malfunction
P0105 Barometric pressure circuit malfunction

Could a bad MAF sensor cause all those?

 

Couldn't find anyone local that had a OEM fuel pump relay in stock. Paid $100 to have one air freighted to me. Starts clicking immediately, just constantly clicking on and off rapidly soon as I get around 2100rpm - 2300rpm

I've ordered a new MAF. Hopefully that fixes it or that's a lot of money to get no where

 

brand new MAF and brand new OEM relay now
still no bueno
error codes are gone, and car idles a bit smoother. But relay still clicking constantly and so loud I can hear it over the stereo

 

maybe a loose ground or bad wire on the fuel pump thats not allowing full connection all the time? mine was corroded and nearly broken in half.
does it happen if you give throttle in neutral or only when youre driving and under load?
how your battery, if not 90% full you can have problems, ive had mine read 12v but would drop to 10v when starting.
youre 100% sure its the fuel pump too? what happenedto your afr at that 2300 spot?
check your throttle position sensor and the IACV too