Eratic Starting, Stalling

Hello everyone 89 XJ 4.0 242 123,XXX miles.... I have searched but can not come to any conclusions yet.

A while back I had noticed a hissing noise coming from the rear passengers side of the car, near the axle. I know that there is a leaky break line on that same side, so could that be it?

Also, I just replaced the IAC & Fuel Filter, and I've gotten a couple random stalls when I let my foot off the gas. Sometimes it will comepletely die, sometimes my rpms will drop & fluxuate. I have even had to throw it into neutral at stoplights so she doesn't stall. This was happening before I replaced these parts too. Also, I tried to start her up yesterday, and it fired, (its hard to explain) but it started going wild, RPM's fluxuating between 0 and 500, vehicle shaking, the lights that were on were flickering, and when I gave it gas, nothing happened. Tried again and same thing. Tried again and it ran fine. It was almost like it was starting and dying over and over again without me doing anything.

Just wondering if any of these problems could be related, or if anyone has had similar experiences. She always ends up getting me from point A to B, but I would like to fix the problem before it turns into something serious, or leaves me stranded. I'm trying to avoid paying more for labor than parts, so hopefully I can figure it out myself. Thanks in advance for all replies.

Joel

I would think CPS. They aren't too expensive and not a huge pain to swap out.

As for the hissing, I am not sure what that would be. Is there brake fluid leaking out? If so, you should take care of that before you go for the brakes and the pedal goes to the floor and you die in a wreck.

Hissing on passenger side rear is commonly the fuel tank venting. Try loosening the gas cap and see if it makes a difference. Have you changed to a locking gas cap recently?

The hissing is not the brake line for sure, but that leak in 10X more serious than the hiss or the stalling.

Eh its a slow leak, I have just been adding fluid every couple months, although I am going to fix that problem soon. Is there any way to check the CPS before replacing it?