Gang,
My good old 96 Cherokee has a slight miss, and has had it since the new engine was put in.
Driving down the road at a steady speed or under hard acceleration it's unnoticeable, it's most noticeable under light to moderate acceleration.
When the new engine was put in it got new plugs, wires, filters, distributor cap, rotor and front 02 sensor.
I assumed the miss was due to the 7+ month old gas in the tank, so I started using Techron fuel system cleaner.
10,000 miles and a gallon or so of cleaner later the problem is still there. Sometimes it almost goes away with the cleaner in it but not entirely. Then something interesting happened last week.I put the new downstream O2 sensor in, and of course had the battery disconnected so the computer would reset. When driving it later much to my surprise for the first 20 min or the engine ran absolutely beautifully, then it stated acting up again.
The O2 sensor operation was successful and the "Check Engine" light is staying out, but something is off enough to keep the engine from running quite right.
So it seems as though when it's in learning mode (using default settings?) it works great, but as it picks up the information from the Jeeps sensors it gets out of whack.
Have I got a sensor going (gone) bad but not quite enough to trigger the light or..?
Any suggestions?
Thanks!
Jeff DeWitt