PT Cruiser Diesel: Rough Idle + Misfires Point to Bad IMC

Had similar symptoms with a 2004 Chrysler Voyager 2.5 CRD. The engine performance dropped significantly and the engine light came on while driving. After initial diagnosis, the manifold flap control motor had failed, causing improper air intake regulation during acceleration. The symptoms matched exactly: rough running engine, reduced power delivery, and that distinct hissing noise from the intake area. The faulty manifold flap was causing incorrect air-fuel mixture, leading to those misfires and poor fuel economy you mentioned. This turned out to be a serious issue requiring immediate attention, as continued driving could have led to further engine damage. The repair involved replacing the complete manifold flap assembly and recalibrating the engine management system. The manifold flap motor was completely seized, which explained the constant misfiring and jerky acceleration. Getting this fixed properly restored normal engine performance and eliminated all previous symptoms. Worth noting that a proper diagnosis with specialized equipment is essential, as these symptoms can sometimes be confused with turbo problems or EGR valve failures.

Thanks for sharing your experience. Did you remember the total repair cost for the manifold flap replacement? My local shop quoted 800€ for parts and labor, which seems steep. Also curious if you had any other intake system issues pop up after fixing the flap control unit? The engine misfire symptoms on my PTCruiser are getting worse by the day, but I want to make sure I budget correctly for the fix.

I just got the repair done last week actually. The total came to 465€ for fixing the faulty intake manifold control switch, which was significantly less than your quote. The repair shop confirmed the manifold flap control was the root cause of my engine performance issues. Since the repair, the engine runs perfectly smooth with no misfires or strange noises from the intake system. Fuel economy has returned to normal too. No other intake-related problems have surfaced in the week since the fix. Your 800€ quote does seem high. Might be worth getting a second opinion from another shop that specializes in these intake manifold issues. The symptoms you describe match exactly what I experienced, and fixing the flap control unit resolved everything completely. Would definitely recommend addressing it soon though, as the rough running could potentially cause additional engine damage if left unchecked.

Thanks everyone for the helpful replies. Finally got it sorted last week. Found a different shop that specializes in diesel engines and they immediately spotted the issue with the airflow control system. The flap control unit was completely stuck, causing all those engine performance problems. Total repair came to 520€ including parts and labor, much better than the original quote. They replaced the manifold flap assembly and recalibrated everything. The engine runs perfectly now, no more misfires or hissing sounds. Fuel consumption is back to normal too. The mechanic showed me the old part, it was totally seized up from carbon buildup. Apparently pretty common issue on these engines. Glad I got a second opinion and found a shop that knew exactly what they were dealing with. All those initial symptoms cleared up completely after the repair.