You swapped the IP's and it's still losing power when you rev it? Hmmmm.
Your return line doesn't look obstructed at all, so that is likely ok. And if you heard bubbles, then you know it's getting back to the tank.
This is a doozy. I would have thought a different IP would have resulted in some different performance at least.
- Just to recap.
- fuel is in the tank,
- fuel is getting to the lift pump
- fuel is getting to the filter,
- fuel has decent fuel pressure to the IP
- IP return is not clogged,
- Swapped IP's, both have a performance lag at higher-than-idle RPMs
That rules out the IP's and the fuel supply and return systems.
I honestly thought you had a bad IP and that would be the solution. But seeing the 2nd IP on it with similar performance makes me wonder...
It could be possible that both IP's are bad, but what are the odds of that.
Perhaps some of the injectors are bad, but I've never heard of a situation where several injectors stuck at once, and even if they did, you'd have some decent smoke even with just one stuck injector.
Maybe we have been overthinking this from the start. What is your air filter/turbo system look like? Is your air-filter really clogged, thus restricting flow, and subsequently robbing power at high R's?