Recently acquired an '84 Volvo 245 wagon (177K miles) for my newly licensed daughter. Driving vehicle home (~600 miles) noticed that when accelerating hard the engine would sputter a bit. The problem has gotten worse over the course of the last 3 months. Now it even sputters when under light acceleration.
Engine is newly rebuilt 2.1L turbo. It sat for > 3 years so I've gone through the fuel system (flushed lines, cleaned injectors, new fuel filter, replaced in-tank fuel pump w/OEM, thoroughly rinsed tank of accumulated " gunk" *tech term*). Replaced O2 sensor. Problem is intermittent, runs fine in the mornings for ~1 mile, then idles rough at lights and sputters on acceleration though still drivable. Fuel economy is acceptable. Plugs, wires, rotor, and dist. Cap all replaced. Compression is within acceptable range, coil is putting out good numbers.
Could this be a problem caused by a fuel pressure regulator? How do I test this? Too expensive to just R& R if not necessary.
Running out of ideas. Daughter has been more than patient but is getting antsy. Any help greatly appreciated. ---Fishsqueezer : (