Well, if my wit has an end, I think I’ve found it. Here’s my problem, and what I’ve done to try and fix it. Any suggestions will be greatly appreciated, as of my two Volvos, neither is running (the other is awaiting a new engine).

Typical situation: I get in the car in the morning, start it right up and drive to the highway. On the way there, I might stop at three lights. Car runs fine—no hesitation at acceleration.

On the highway, the runs as well as it ever has. Acceleration is fine, kicking it down when I have to works. In short, you wouldn’t be able to tell that the car has something seriously wrong with it.

I get off the highway, in the city now. I have to drive another 4 miles or so, in fairly heavy traffic, and through several lights. When I stop at a light in traffic and wait, the trouble starts. Eventually, the rpm’s will decrease and the car will start to shake a little, and then I know that I won’t make it through the intersection. Sometimes, it will stall where I’m sitting. Sometimes it waits until I get into the middle of the intersection to stall.

After maybe the first or second time it does this, it will start right back up and I can go again. But after it’s done it several times, the car will start, but it will barely idle, and won’t rev when I press the accelerator. Sometimes, pressing the accelerator will stall the car. After trying to start the car many times (today I sat through 3 lights), it will eventually come back to life and get me a little farther down the road. The problem then gets progressively worse.

An intermittent buzzing sound comes from the general location of the fuel pump at all times. I think that when the buzzing stops, the car stalls—but I’m 100% sure there’s a pattern.

What I’ve tried to fix it: new spark plugs (it had new distributor, cap, rotor, and wires a few months ago), new air filter, swapped out the AMM with one that I know works, replaced the fuel pump with a used one (did not do the fuel filter—that was supposed to happen tomorrow, but the car was dead), swapped out the fuel pump relay with one that I know works, increased the idle speed, added fuel injector cleaner to the tank.

Also, I don’t notice any difference when the tank is full or nearly empty.

Many thanks to anyone who can offer suggestions!

Milan