Have a problem with ECU voltage on boost.
My IAW monitor shows 13-13.5 volts on idle and on other run modes.
But if the engine is hot the voltage drops below 12V (11.5-11.8) on maximum boost and the engine is misfire.
I've replaced alternator but no changes.
Have checked the fuel pressure but it's ok (rewired).

Don't know what to do next. Need help, mates.

4x4, 803, T34, 071C-0.65mm gap, closed loop, chipped by Stu