1996 Prado with 1KZ-TE and manual trans - Loss of power on higher grade inclines

[WPThunder25]

I've started to have some issues on some of the higher elevation passes here in Colorado. Had an issue up Berthoud Pass yesterday which is a 6.3% grade at its steepest point. When I get around 2.5k RPM in any gear it will start to stutter and blow some dark grey and black smoke. I cannot get it really past 2.5k RPM either. I get a check engine light and then something turns off, maybe the turbo, and I can go back above 2.5k but with a very apparent lack of power which is why I'm thinking the turbo shuts off. Once I get back to a normal grade the engine light goes away shortly after and the power returns but will stutter again if I try to go above 2.5k. I just changed the air filter hoping I could find an easy fix but it was no help. Any idea what the issue could be?

Everything is stock as far as I am aware. Let me know if I can provide anymore details.

 

[javelinadave]

First and cheapest items of suspect are a dirty air or fuel filter. Either could coast that. Next would be bad fuel followed by clogged injectors. After that I would suspect a gummed up intake or a failing fuel pump.

 

[WPThunder25]

I have a fuel filter laying around so I’ll give that a try. Thanks!

 

[KiwiBogan]

Hmm, if you could pull the fault codes and share them here, that would be very helpful.

The black/grey smoke sounds like a symptom of lack of air (air:fuel ratio being messed up). So id be thoroughly going through the intake system looking for blockages. EGR would most likely be the culprit but it could also be as simple as one of the vacuum tubes from the intake manifold has a leak, has popped off or collapsed under heat. The flexible rubber hose from the air filter box to the harder plastic pipe that passes across the front of the engine to the turbo can collapse when it gets too hot under the bonnet especially if that hose has been replaced at some stage as aftermarket ones don't have steel wire core in them to prevent them collapsing. They will return to shape again when you stop accelerating so it's hard to spot this problem when you pop the bonnet.

The feeling like the turbo has stopped sounds similar to the TCV broken wire/connection issue I've been having lately, just without the smoke. The other symptom of this is a knocking sound at idle/low revs. I've also had a broken wire at the TPS connector wire which caused a similar symptom again without the snoke but I don't think your model has the TPS at the throttle body?

Check if you're burning through oil. Could be seals in the turbo are shot. Though you would notice the symptoms during normal driving too of that was the case.

I would doubt it was the injector pump.

Try and get some codes to us so we can help narrow the problem down