My '88 740 GLE has always run like a top, but a few days ago, it started running like crap on hills. It doesn't miss or cut out, but when I climb a hill, there's an extreme lack of power. No black smoke, incidentally. It starts, idles and runs like it always has otherwise. It seems to me like a fuel starvation issue. I just changed the fuel filter but it didn't help. My air filter is only about 9 months old and doesn't look dirty.

This may or may not be related, but a few days before my lack of power issues, my car started making an intermittent rattling noise from underneath that I can't seem to locate. Could just be the heat shield, or I guess it could be the catalytic converter (which, if bad, would explain my loss of power issues). I'm thinking it's time to bring it to the shop, but I'm super broke on account of I'm moving out of the state in a few weeks.

Any input would be much appreciated. Thanks!

Thanks for the input. Just wanted to follow up: It was the catalytic converter and it wasn't cheap, but it wasn't too bad because I take the car to a great Volvo guy for stuff I can't do myself. It really did sound like a cowbell, Smitty, so thanks again for helping me diagnose it.

This one's easy - just not cheap.

Your cat died. More specifically, the internal structure has failed and shifts around and blocks the exhaust flow, killing power. Never enough to stall the engine, just no power. Happened to me on my '88 245 at around 200K miles, and that telltale "cowbell" rattle from the cat was the tipoff.

Sorry to say, replacement is the only fix.

Hey, thanks a lot, Smitty. I really appreciate the input. After much amateur troubleshooting, it's really starting to look like the converter is the culprit. That's kind of what I was afraid of!

First check trans fluid, determine whether its is engine or transmission related.

"It doesn't miss or cut out, but when I climb a hill, there's an extreme lack of power. No black smoke"

Is there any other color smoke? CEL? Temp running hot?

Hey, thanks for the response.

I will check the transmission fluid, but it really seems like it's shifting fine. No smoke whatsoever. No engine notification lights at all. My temperature gauge has been mysteriously dead for some time now, unfortunately, but the car is definitely not hot enough to lose any coolant or display any other obvious signs of overheating. Also, I've heard that a bad catalytic converter will glow red hot, but mine doesn't.

I still haven't ruled out the in-tank fuel pre-pump. Supposedly, if that pump's bad (either inoperative or just a clogged "sock), the car will run fine with a full tank, but it will start acting up when the fuel level gets low. I'm going to go fill the tank and drive up some hills to see if there's any difference in performance.

Again, much obliged for the input.