I have a 1991 Volvo 240 sedan. It has 62,000 miles on it. Recently, it has started to “almost stall” on acceleration. This usually does not happen when I first start the car. It will more commonly happen after I park and then start it again. On giving it a little gas it severely hesitates but does not actually stall. A few times I heard a pop as it started to gain normal acceleration. This problem occurs in about 10% –15% of accelerations from a stopped car. It seems that the problem does NOT happen when I have a full tank of gas.
Could the gas filter be the problem? Two years ago I failed an emission inspection (needed an new 02 sensor) and was advised to use a gas cleaner now & then. It worked and last year I passed with no problems. The car does NOT have turbo. I had a tune up and new wires, cap etc done 15,000 miles ago and have cleaned out the PCV flame trap filter recently. Any ideas will be greatly appreciated.