Originally Posted by bigb229
fuel pressure checked out ok. think i have some valve float. gonna pull the head and have it machined for performance springs and drop a comp cam over in it
How high in the RPM band was the backfiring occurring? Typically valve float is seen at high RPMs near or beyond redline.
Did you not replace the springs when the head was off last?
His: '00 WJ 4.7 Limited- Zone 4" SA lift, JKS BPE's
Hers: '03 WJ 4.7 Laredo- IRO 3", 245/75/16 Duratracs, Bilstein Shocks, JKS TB w/KOR Bushings, Rusty's A-Arm Spacer, CORE4x4 Adjustable Front Control Arms, Dynomax Exhaust, RB1 Nav -Coming Soon- Overland Rock Rails