Justy Diesel: Rough Running and Power Loss Symptoms

The symptoms you describe match exactly what happened with my 2004 Subaru Forester diesel. The engine performance issues, particularly the rough idle and power loss, were indeed traced to a significant intake manifold leak. The manifold pressure was dropping due to scorching around the gasket seal. This created vacuum leaks, leading to engine misfire and inconsistent air-fuel mixtures. The check engine light was persistent due to the sensor detecting these irregular readings. The repair involved replacing the entire intake manifold assembly as the warping from heat damage was too severe for just a gasket replacement. This was a serious issue that needed immediate attention, as continuing to drive risked further engine damage and potential failure. The exhaust smell you mention is particularly concerning, as it indicates exhaust gases are likely escaping where they shouldnt. When my manifold was removed, there were clear signs of heat stress and deterioration around the mounting points. Getting this fixed properly the first time is crucial. The repair requires careful attention to torque specifications and proper gasket installation to prevent future leaks.

Thanks for sharing your experience with the manifold issues on your Forester. Your symptoms were indeed very similar to what I am seeing with my Justy. Quick question, do you remember roughly how much the intake manifold repair cost in your case? Also, has everything been running smoothly since the fix, or have you noticed any related engine performance problems?

After getting the intake manifold fixed, my Forester has been running perfectly with no engine performance issues whatsoever. The repair cost me 1180€, which included replacing the defective intake manifold assembly due to the scorching damage. The manifold pressure readings are now stable, and the check engine light hasnt come back on since the repair. The engine runs smooth at idle and acceleration is back to normal. No more exhaust smells or engine misfire problems either. It was worth every cent getting it done right at a reputable shop. If your symptoms match what I experienced, I strongly suggest getting it checked soon to prevent additional engine damage. The longer you wait with intake manifold issues, the more expensive the repair can become. Looking back, the only regret is not addressing it sooner when I first noticed the performance issues. But once fixed, these manifold problems typically dont return if the repair is done correctly.

I took your advice and found a new mechanic who specializes in diesel engines. The diagnosis confirmed a cracked intake manifold causing vacuum leaks, just as you suspected. Total repair came to 1350€ including parts and labor. The check engine light is finally off and the engine runs great now. No more jerking during acceleration or rough idling. The manifold sensor readings are back to normal and the exhaust smell is completely gone. The engine misfire issues cleared up immediately after the repair. The mechanic showed me the old manifold and explained how the cracks developed. Really glad I got it fixed when I did, apparently it could have caused serious engine damage if left unchecked. Thanks again for helping me identify the problem. The car feels like new again.