Hi! I own a 2004 Chrysler Neon LX with 125k kilometers on it. I've owned it since new and I love the car still. Just two weeks ago I had the transmission cooler in the radiator break down and trans fluid flowing to the radiator. Luckily it all happened in my parking lot so supposedly no harm to the transmission was done.

I got the car towed to the local authorized Chrysler/Dodge/Jeep service to get the cooling system and transmission flushed, radiator and transmission filter replaced and of course new transmission fluid and coolant filled. So after waiting a few hours and paying the bill, which was about 1000USD (damn it's expensive in Finland) got the car back repaired and tested.

Drove about 15 kilometers and the car started acting strange, rpms going from normal idle 700rpm to 3000rpm back and forth without me pressing the pedal. Then I gor the car parked on the side of the road, turned it off, started it again with the same symptoms, maybe even worse and then the car stalled. I then had it towed back to my house because I really didn't want to pay any more money before I'm sure what's wrong with it.

I got the codes and there was this P2074 Vacuum leak. I have now done a visible check on everything I can think of (throttle body, intake manifold, brake booster line, pcv line) and none of them seem to have anything wrong. Is there something I'm missing? Can it be some defective sensor or would it throw a code on that sensor as well? When replacing the radiator is it possible they've touched something that might have loosen up?

Thanks for your help, any advice is needed and appreciated!

 

Oh yeah and the brakes don't work as they should but I guess that's normal when having a vacuum leak.

 

If you have some brake cleaner or carb/throttle body cleaner, do quick sprays on each vacuum line. If the idle changes, you found the culprit. Also check the bellows tube, it's the piece between the throttle body and intake manifold.