So I've started a ton of threads over the last few weeks since my car had 30 problems at once! (Bad alternator cable, bad MAF, bad MAF Relay, blown header gaskets, fouled plugs and bad spark plug wires).

After I fixed all of those problems my car has been running much better. The engine is quieter, I can rev it up to 5000 with ease and it feels faster. However, over the last few days my car occasionally bogs and wants to stall when braking (usually hard stops), sometimes during slow turns (think turning into driveway/15 MPH backroads) and sometimes after I start the car, after it warms up when I first shift in Reverse or Overdrive it acts like it wants to bog down then quickly recover.

Some drives it does it during all of these situations other drives not at all other drives only one or two. (Under braking/turning being the most common).

During braking it will bog down to below 500 RPM and then recover to 650-700. Same with when turning and first putting it into gear/reverse.

The gear/reverse it only seems to do that when my car is cold on it's first start, after it warms up it's fine.

 

Are you also braking in the slow turns? I'm thinking if the symptoms occur only when your foot is on the brake, maybe check the brake booster for vacuum related issues?

 

I was thinking that earlier. The symptoms only seem to occur when I step on the brake pedal. They don't occur in Park or Neutral at all.
I'll check that big vacuum line that runs from the booster to the manifold tomorrow.

 

Vacuum.

Check COMPLETE lines system + gasket related + rubber air inlet for cracks

 

Ok, so I think I've narrowed down the problem. I'm 99% sure it's either the brake booster vacuum line that runs from the booster to the manifold or one of runs underneath the driver side fender.
I've replaced all of the other lines in the past and those are the only two. I'm sure that brake booster line is original as it says 12/06/85 on it.
Does anyone know the size of the brake booster line? I think I might have to order line as the autoparts stores are always sold out these days.


Does anyone know what size this is? 3/8? 1/2?

This runs under the driver side fender, the only other line I never replaced. it does look brittle. Anyone know where it runs too?

 

I replaced the vacuum line that runs from the brake booster to the intake manifold. (It's 11/32) and it made a small difference. Idle is more stable but sometimes at low speeds (usually when braking) my car still bogs and sometimes stalls.

Does anyone know where that vacuum line in the above picture runs too? I tried looking under the car and can't find it. Don't tell me I have to pop off the fender...

 

It goes to the vacuum ball. I think it's mounted under the driver's side battery tray?