hshawn31

i have a 97 cherokee sountry edition, inline 6 with 260,000 miles. I got a code of 43 which is misfire in one or more cylinders...i am getting horrible fuel mileage. I just replaced all the spark plugs, all wires were tightly attached to the plugs ( yes, i checked ). What elses can cause this misfire? And does the misfire cause poor fuel mileage? Also, this may or may not be related, but when while i am sitting idle at a stop light for example, the idle is rough, kinda lopey too....hard to explain.

Finally, when downshifting, after the jeep has been run for a few miles, it will not shift back into first without me manually shifting it to first then back to over-drive. Why is this? It shifts fine otherwise....

VTJeep

Maybe o2 sensors.. the tranny thing is odd. What about TPS or IAC?

hshawn31

the TPS is brand new, as is the MAP sensor. I dont get a code for the o2 sensors. I did get a code 66, which i have no clue what that is, its not even in the manual i have lol. i got the code 66 and the misfire code. Tranny fluid is full, even added some Lucas tranny stuff to it. No change. It gets annoying at every sto light and stop sign to shift down to 1-2 and then back to over drive