Misfire on a Pull

patmcclelland

Our Town Car has been great for 260,000 miles with upkeep along the way. It has now developed a slight but irritating missfire between 40 and 60 mph on a pull at light throttle. It shows no codes. I had a real mechanic test for codes with his Snap-On reader; no codes. I had a good transmission man convinced that the original trans finally needed a rebuild but when he drove it he said the trans was good; it is a missfire. I replaced the fuel filter and 2 coils with questionable boots. 5 coils have been replaced. What do I try next?
Thanks
Pat

Mr_Shiftright

Well the fact that it only happens at about the same time your transmission would normally shift into or out of overdrive does still make the torque converter suspect. Perhaps if you're due for a transmission service this would be a good time.

If you had a misfire, then the more load the more severe the misfire. So if you can go up a long hill in top gear and not have noticeable misfires, I'd suspect the torque converter is locking and unlocking in and out of overdrive. Is there any "shudder" or is it a really "snap" type of hesitation?

patmcclelland

I thought "torque converter" also because a similar malady was addressed with a fluid flush by Lincoln 98000 miles ago. But my trans guy turned down a $1200 job because he felt a snap instead of a shudder. Also, turning the OD off doesn't solve the problem. Thank you for your help and any more ideas you might have.
Pat