Car: 1995 Saturn SL1 SOHC, standard transmission, 4 cyl. Mileage 237,000 Km
Symptom: Hard to describe here but perhaps as ?hesitation?? Either while running or at idle, engine seems to hesitate. More noticeable on the highway, pressing the gas pedal the car will on occasion jerk, lurch, sputter, or hesitate?. It is not continuous, but only very brief and at random.
My thoughts: It does not appear to be the clutch slipping. It does engage well, I can slowly accelerate uphill engaging the clutch with no lurching at that point.
I last changed the fuel filter at 142,754 Km (July 2004). The Haynes manual suggests the fuel filter be changed every 48,000Km, but I talked with a mechanic and he suggested every 100,000Km is OK, so I?m about near that. The fuel pump sounds OK, nothing particularly different than usual. I have used fuel injector and fuel system cleaners over the years, maybe 2-3 times per year. I also have used oil supplements, Bardahl B2, during the last 2 oil changes, (done every 5-6000 Km). I hear and feel the hesitation from the engine both at idle and when driving.
The injector coils, cables and spark plugs are OK. I have had a failed coil before and recognize the power loss that occurs when this happens. This is not similar.
I failed the emissions test in Dec 2008, and got the conditional pass. 2 tests failed for NO, revealing that the catalytic converter needed replacing, which I haven?t done yet. The O2 sensor was a little lean but was within spec. The exhaust seems to have no block from what I can observe, perhaps it?s partial.
Suspension, steering, brakes are all OK.
Any suggestions?
Much Thanks in advance.
Cheers, Roger