1991 Regal Ltm. Problem

[Shadowhax]

Ok, so here's the problem: I'm driving my car, everything is going just fine until my RPM gauge drops to about 340, then completely down to zero, killing my engine. I tried starting the engine again, but all it would do is turn over. I left it over night until I could get a tow from my brother, and he checked it out himself the next day. The car started just fine, we drove it back home, where it died as I turned onto my driveway.

Before, my check engine light was on, but I took no real notice of it, since the car was running just fine. In light of recent events, I ran a diagnostic and it threw me a "43" code: knock sensor. I've replaced the knock sensor since then, and took it out for a spin. No engine light, but same problem.

I asked my dad at this point, and he said it could either be the fuel pump or the fuel relay. Not being one with much money, I chose the relay, in hopes that that was the problem. Still no dice.

Before I go out to get a new fuel pump, I wanted to run this by you guys here, in hopes that one of you might have run into this problem before.

Thanks, in advance.

[HotZ28]

When it dies, check for proper fuel pressure & spark.