Greetings Maxima.org forums!

I drive a 2000 i30 and i'm trying to get rid of the P0171 (engine's bank 1 running too lean)

I'm suspecting a vacuum leak as i'm hearing a strong hissing sound coming from the throttle body area.

So far i've replaced the upper intake manifold gasket and the intake air duct (the latter had a pretty massive crack

)

No seriously, massive crack =D

In the process of replacing the gasket i snapped two vacuum hoses, one that i already replaced and the other one is the one that goes to the swirl control actuator which i patched with a plastic connector and some heat shrink tubing

Now i'm wondering what i should do next.

It is on my todo list to replace the swirl control actuator hose but it doesn't seem to have a massive impact on the engine's behavior and considering that the hissing noise is not coming from that area i'm pretty sure there are more important things to be taken care of

So i guess my next question is: how to properly confirm that there is a leak in the throttle body area?
I've heard of the propane torch option but i feel funny about buying a propane torch, using it once for this job, and then storing it somewhere where it's going to be as useful as a mini-bomb collecting dust

Any thoughts? Ideas? Suggestions? Comments?

 

I have never heard of using a propane torch for vacuum leaks, but I suppose the process is to not light the torch and let the propane gas come out as you move the torch around from spot to spot. It is much more common to go buy a can of starting fluid (ether), carb cleaner or brake cleaner.

The cleaners are the most volatile so you don't have to be as right on target to let you know that you are getting close, but will also take paint off. Starting fluid is a little less volatile, but doesn't harm paint. Propane is the least volatile of what I have mentioned, but would still do the job.

 

Thank you for your quick response, DennisMik!
I'm planning on working on the car tomorrow so i'll try spraying brake cleaner around the throttle body and keep the thread updated

 

So i worked on the car today and found out that the hose that i replaced the snapped one with was too weak to withstand the vacuum and would actually warp due to the "pressure"
I replaced it with a way stronger one and things have improved...but just by a little bit
The car still experiences hesitation, rough idle, clicking around 2000 rpm and of course power loss
I can still hear a hissing noise coming from the upper intake manifold, i'd say somewhere between ignition coil 3 and 5
I tried sending smoke inside the engine with a cigar (kinda like this: ) but i wasn't able to find any leaks
Any ideas as to what can cause this situation?
I'm considering replacing the two lower intake manifold gaskets as i've already bought them but i'd love to avoid the hassle if possible

 

I'm not too sure about that video and using a cigar. I think that is a lot more difficult than it looks.

I'd give it another try with the spray can.