Hi, My 89 240 Volvo started off with an occasional "shudder" on takeoff from stop. This progressively got worse (more frequent but same symptoms) over a month or so to where I didn't feel safe taking it out on the road. During this time it "stalled" during idle a couple of times, but, always seemed to run fine after accelerating to normal speed. No check engine codes! Things have gotten worse with the last two items I've changed. See below.

I detected a high pitch "whining" sound coming from the main fuel pump. I replaced the fuel pump and fuel filter. The "whining" sound is still there. I also changed the Throttle Position Sensor.

Neither fixed the problem and it seems it actually is worse. Now, the Volvo will start ok, but, runs very rough when pressing the accelerator (almost like a constant miss. If I start it and leave at "idle" it will idle "ok" (little rough) and then shuts off abruptly after 30-45 sec idle. It will re-start immediately after and repeats this constantly.

It's obvious the new Fuel Pump and TPS did not fix the original problem, however, could the new fuel pump be bad? I put the "old" TPS back in with no change in behavior.

Looking for suggestions. Could the fuel pump "whining" be a clue to what is really going on? Have not tested the "in-tank" pump. Could this be a possible problem or what about the Fuel Pressure Regulator?

Don't want to have to have it towed to mechanic if I can avoid it. Any help would be greatly appreciated. Thanks in advance!