Hyundai Galloper Power Loss and Hissing Sound: Possible Swirl Flap Control Error?

Hey! Sounds like what I went through with my 1997 Hyundai Terracan, honestly. Definitely a bit rocky there. Had similar symptoms like yours: shaky idling, decreased power, and got the check engine light shining like a beacon. It ended up indeed being the intake manifold control. The intake manifold has these things called 'swirl flaps', they help create a swirl of air to help with fuel-air mixing. Oftentimes, carbon deposits can cause them to stick or even the actuator that opens and closes them might fail - that seems to cause most of these symptoms. The hissing sound might very well be a vacuum leak. When a part of the intake tract leaks, the engine 'inhales' air that hasn't been measured by the MAF sensor causing such imbalance. Mechanically speaking, it wasn't a small issue, needed quite a bit of work with replacing the intake manifold. Nonetheless, the garage experience was okay. Mechanics knew what they were doing, so they took care of it properly. So yes, stick with your hunch, could very well be a swirl flap control error on the intake manifold — pretty much the experience I've had. Good luck!

Hey, thanks for weighing in on this with your past experience. Sounds like what you faced with your Terracan is almost a mirror image of the issues I'm dealing with. On a side note, do you recall roughly how much the garage charged you for the intake manifold replacement? It'd be great to have a ballpark figure before I go hunting for a decent mechanic. Also, have there been any more problems with your Terracan since they fixed this issue? Appreciate your help!

Hey there, No worries, glad to share my two cents. The overall fixing charge for the intake manifold control hit around the 465.00 € mark. It's not exactly penny change, but for what it's worth, the process was pretty comprehensive. That said, ever since that last visit to the garage, my Terracan has been running without a hitch. The swirl flap control error on the intake manifold was thoroughly taken care of, no repeats of the former issues. Even the temperamental hissing stopped! Just keep in mind, finding a good mechanic who knows the deal is key to getting it sorted properly. Best of luck with your Galloper! Keep us posted, will ya?

Definitely appreciate you getting back to me with those specifics. €465 sounds hefty, but if it gets my Galloper back to optimal running condition, it'll be worth every cent. Very reassuring to hear that your Terracan has had no repeats of the same problem after the replacement - certainly helps to put my mind at ease, thanks! I'll start looking for a decent mechanic who knows his stuff about the intake manifold and its complexities. You're right, the mechanic’s expertise is a game changer in these situations. Will keep you all posted on the progress. Thank you again for the helpful advice! Cheers!