F250TXR surging and backfiring

[captain rednut]

hi my engine is running great for about 20 mins and then looses power and occasionally backfires and other times just wont over certain revs at all.
The YDS shows no fault codes present but highlights in (red) when sea trialing the TPS sensor (ONE) and throttle valve opening.
The voltages are normal as to specs. Do you think the TPS is faulty?? or any suggestions??
Also its just had a new complete vapor separator fuel system fitted from extensive ethanol damage.
any help appreciated??
regards CR

[rodbolt17]

depends on why it highlighted the TPS voltage.

backfire typically indicates a lean A/F mix in the intake manifold.

[captain rednut]

hi rodbolt
it especially highlighted the stated sensors in red when the problem occurres, it only backfired the once in the test run yesterday but runs rough and looses power and then picks up again?? it will run under 3500rpm gently all day its only when you run it around 4500rpm plus it plays up but when it starts running rough it slowly dies to a idle. i thought the very contaminated fuel pumps i replaced may have fixed it in the first place but it didn't. any other ideas??
thanks cr

[rodbolt17]

sounds like two issues.
one monitor rail pressure.
the other post the highlighted voltages.
faulty/clogged injectors will do this as well.