Hey folks.. I'm stumped. I have a 99 4.0 XLT 4X4 with about 138-139k miles. I bought it about 6 months ago and it was great. Recently, ive had a slew of issues. Ive thrown multiple codes, including generic misfire, misfire on 4, 5, 6, az well as others. Also, its thrown some o2 sensor codes...