Greetings,
I have an '87 240DL wagon, and have been chasing a morphing problem for months. It started with an occasional hard start and hesitation on acceleration (starts to go dead at first, then "catches" and rpms rise). Did some tests, and based on what I found fixed (in this order): new air mass sensor and thermostat in the air preheat system; cleaned throttle body; new O2 sensor.

At this point I stll had the hesitation, and I began having starting problems where the engine would fire up the second or third time I cranked it, every time. I took it in to my favorite Volvo shop, and they put in a new check valve. When that didn't fix it, they did a fuel pressure test and said it "might" be the transfer pump in the gas tank. The starting was getting harder (wouldn't just start after two or three cranks), but sometimes it would seem miraculously fixed, and start fine for a several days (up to a week), then go back to hard starting (anytime, hot or cold). I replaced the transfer pump, which I determined was in fact not working. That works now, but the starting is still hard, and getting harder. Have to crank and crank before it'll start, and once it catches, it sputters and wants to die, and I have to kind of feather the accelerator to coax it into life. The hesitation on acceleration is still there, and somewhat worse (takes longer to come out of "dead" mode and catch.

I've got Bentley, and think maybe I should buy a fuel pressure gauge and fittings so I can do those pressure tests myself. Once it's started, the car runs pretty good, except for the occasional acceleration hesitation.

I've also checked the 25 amp fuse in the engine compartment (per suggestions on this list).

Any ideas on where to go from here are much appreciated.

Steve