Hi all! First post.

I'm experiencing some issues with my 5. I'm hoping listing out all the issues will maybe help someone that knows these cars well give me a good starting point. I'm also wondering if all of these issues could be related to a single problem as they're all vacuum/exhaust/emissions type issues as far as I can tell.

First and foremost I have no CEL. Car is not leaking any fluids that I can tell. Car starts every time without struggle.

ISSUES:

1. I'm experiencing surging upon acceleration especially when the vehicle is cold (I'm in ohio and things are chilly right now). When you dig in to the gas you can feel it "gasp" for a moment and then finally kick in and pull. I don't think it has the power that it should.

2. When car is in gear and not moving (stop sign OR parking brake + Drive or Reverse) and brake pedal is depressed the idle drops to 400-500rpm and the idle shakes the car a bit. It never stalls, it just idles rough. Let off the break and it goes back up to 750-800rpm

3. I have no doubt I have an exhaust leak. Exhaust is a bit noisy at idle. I get a gurgling / crunchy noise when accelerating higher RPMs 3000-4500. If the car is in park and I get the RPMs that high when I let of the gas I get an exhaust "fart", the needle jumps a bit and then goes back to normal idle slowly.

4. My blower in the car will not switch between front, defrost, floor vents. No matter what position I have it in it always blows out of the front/floor but not as much as I think it's supposed to.

What I've done so far:

1. Throttle Body Cleaning - No Change

2. Replaced PCV valve & hose (read that these are known for going bad - this was a 5 hour project of removing intake manifold to access) They both seemed fine but I replaced them anyways while I was in there - No Change

3. Checked EGR Valve stem to make sure it wasn't stuck (took top portion off and it moves freely up and down)

4. Verified brake booster is holding pressure with brake tests

5. Sprayed carb cleaner around all vacuum joints I could reach with no effect in idle.

My initial thoughts were leak in break booster vacuum line. These lines are $140+ and a dealer only part (they're hard plastic lines, not rubber hoses and the check valve is molded into it) An auto parts store employee told me that just because the engine looses vacuum when I press the break at idle doesn't necessarily mean it's that line. When the brakes are depressed they pull enough vacuum to cause the real leak to become worse. Thus I didn't want to throw a $140 part at it.

I examined the exhaust that is visible underneath and didn't see any large holes or separations in the joints. The joints don't look great (nice and rusted) but weren't coming apart as far as I could tell. I don't think the exhaust is clogged as I get plenty of exhaust mist in the cold temperatures.

Any recommendations for the best place to start in further diagnosing my issues?

 

It sounds like your exhaust leak could be a symptom of a partially clogged converter. I would attack that first. The heater not switching modes is likely a disconnected/cracked vacuum hose. It requires very little vacuum to run the mode doors so it could run close to normal with a leak in that vacuum circuit. When cleaning the TB a relearn must be performed to correct the idle. You can disconnect the battery and turn the ignition on to clear the memory.
If the converter is damaged i would assume the car is in need of a good tuneup/injector flush/decarbon as there are no moving parts in a converter to fail. A bottle of Techron in the gas tank will clean the injectors and decarbon the valves.