I have a 1994 "L" code Trans Sport that has had a history of surging/bucking at light throttle, around 80-95kph. ( 90 just happens to be the speed limit on our "Urban Expressway") In the past (on 3 occaisions) the O2 sensor stopped clocking and stuck at about .45 volts. Replacing the sensor made a big difference each time.(problem either totally dissapeared or was reduced to the point it was no longer noticeable) The sensor is working fine now, about 16-20 crosscounts on the diagnostics - and block learn andadaptive readings are 127-128, right where they belong. I'm suspecting it could be an EGR problem? Also the knock count is up from where it used to be - used to be able to drive 30Km or more and only have a 6 or 8 count. Today, going 10K I was over 230 - using the same regular gas as usual (likely about E5 or E10 mix, 89 octane (R+M/2). Engine is not overheating (208F after a good run) Getting about 13.5 L/100Km mileage - not great, but not a whole lot worse than normal. Just had 2 coil packs go bad a couple months ago - replaced them and the "hunting" problem has not gone away (or gotten worse). The engine idles very smoothly, and pulls well under load.
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