2003 VW Golf - Engine shuddering, accelerating slower

golf
volkswagen
misfire

#1

Hey folks, I’ve been having this issue for a few days, and your guidance would be greatly appreciated!

My engine started shuddering rather considerably a few days ago, seems to be misfiring. Happens both while idling and accelerating. Thought it could be a bad spark plug, and was prepared to replace them. Which is doable, but not easy, considering they’re not very accessible with this particular engine. But when I lifted the plastic cover off the engine to take a look, I noticed this tube (circled in picture) had been worn away considerably in one spot. In fact, it’s barely attached.

Now I’m no expert, but I’ve read that a leaking or disconnected vacuum hose can cause exactly the type of issue I’m experiencing. I’m wondering if the object pictured is in fact a vacuum tube. Might that be the issue? If so, how easy would it be to repair it myself? I’m not very experienced with making my own repairs, but I’m good with a set of tools, as long as I have instructions. Thanks!


#2

I don’t know what that tube is for, but it appears to connect directly to the intake manifold. If so and it is breached, that would allow unmetered air into the engine and would indeed cause this type of symptom. It might start out as the engine idling a little faster than before, and progress over time to a stumbling misfiring engine, worse at idle than when driving down the road. Modern engines have to be completely air tight to run correctly, from the engine air filter box to the exhaust pipe.


#3

Any kind of vacuum leak can cause rough running. I can’t tell from the pic if that hose is actually leaking but if it is the rough running could be caused by several things.
One would be the actual vacuum leak itself and the other is the fact that hose appears to run to the fuel pressure regulator.

The FP regulator is controlled by engine vacuum from the manifold. That should be an easy fix with a length of any type of appropriately sized vacuum hose. It does not have to be similar in appearance.
If the hose is replaced and the problem still exists then you need to consider a miss caused by a spark plug, coil, etc.

Is the Check Engine Light on and flashing?


#4

Thanks to both of you for your quick and helpful responses! Yes, ok4450, the check engine light is on and flashing.


#5

“the check engine light is on and flashing.”

Since you tell us that “I’m not very experienced with making my own repairs”, I would strongly suggest that you get the car to a qualified mechanic a.s.a.p.

Every moment that you continue to run the engine in this condition increases the probability that you will damage the catalytic converter, and might even do further damage to the engine.